It’s been a touch over four months since I first published the Stages Power Meter In-Depth Review. It was interesting to me in that a lot of people took very different things away from the review.
As a result of that review, Stages made a number of updates to their power meter firmware since then, including addressing specific items that were raised as concerns during the review. Based on that, I continued to ride with it. Every single ride for months. They provided iterations of new firmware updates, and I updated. Rinse and repeat.
Except, it wasn’t just riding with a single power meter. No, it was riding with 3-4 power meters concurrently. And 4-7 head units concurrently. One of the Slowtwitch editors recently noted something along the lines of ‘The fun factor of these rides were approximately zero’. Which is pretty true here as well. Aside from being a cold and rainy winter, there’s far more complexity in ensuring that every setting and start/stop time is exactly the same when you have so many head units and power meters running concurrently.
I’m reasonably confident that outside of Stages themselves, I probably have the largest and most complete data set of a single rider against as many additional power meters as one can technically attach to their bike. I do note ‘single rider’ because again – this is just me. It’s not as though they gave me 10 crank arms to test with and assign to random people. And quite frankly, I wouldn’t want that. That’d be a nightmare. And it’d be useless without the same painstakingly strict test protocols that I go through. Protocols that no sane person wants to deal with every.single.ride.
If you’re just finding this page without going to the original review, I encourage you to go to the original review to get a grasp on how the Stages Power Meter works, unboxing shots, and all the usual background information.
A look at the testing methodology:
If there’s anything I’ve learned (or can note to others), it’s just how difficult it is to accurately test power meters. Going out for a ride with two power meters isn’t a test of a power meter. It doesn’t tell you who is right or wrong. It just gives you two power plots. It can tell you and show you potential abnormalities, but not absolutes. It cannot be used to perform a full comparison review. You must have a 3rd unit to provide perspective. Speaking of that 2nd (or 3rd) unit, making the assumption that the Quarq/PowerTap/SRM/Power2Max is always correct is fundamentally flawed. How do you know? What calibration procedures have you done? And have you done them correctly? Even then, as I’ll show you below, it’s easy to make some of those units go askew in certain conditions. Knowing those conditions is critical.
The same goes for data collection. Each head unit records data differently, and finding ones that record data the same way is critical to testing. One of the tools I got added to my bag for these tests was the WASP unit. The WASP allows me to simultaneously collect power meter data from an unlimited number of ANT+ power meters (or other ANT+ accessories) concurrently.
Further, not only does it collect that data concurrently with a timecode, it also collects at a higher rate than a typical Garmin (or other head unit). Normally Garmins will pick one of the 1-8 broadcasts per second, and record that. Whereas the WASP will collect all samples per second and record the average of those.
You can see a screenshot of what this data looks like below:
Which isn’t to say I just used the WASP. Nope, almost all of my rides has between 4 and 7 head units recording concurrently.
This means that every single time I was following a set procedure on how to collect the data, which included:
1) Validation that each power meter was paired to the correctly labeled head unit (validation of ANT+ ID against known PM ANT+ ID)
2) Validation that each power meter did a manual calibration prior to the start of the ride
3) Validation that each head unit was recording at the same settings (1s recording, cadence and power zeros included)
4) Validation that all were using an external speed sensor for indoor rides, and that all circumferences were set identically
5) Starting all head units at exactly the same time (creative use of fingers)
6) After the start of the ride, validate that all sensors were correctly transmitting
7) At approximately 10-15 minutes into the ride, stop by the side of the road and manually calibrate all units
The calibration procedure included stepping off the bike, but over the top tube. Then putting the cranks in the 12/6 position, and then manually calibrating each unit.
Post ride, all of the data would be collected into a single folder and then labeled by power meter and head unit.
While this sounds somewhat simple, doing all seven steps 4-7 times (for each head unit/power meter combination) really adds up.
And that’s all before I even start analyzing the data. Which usually takes hours per ride. There is no application out there today that can cleanly generate all the charts and data plots you see in this review. That’s all done with Excel, painstakingly. A simple 90 minute ride has over 20,000 power meter data points alone to correlate and analyze.
Ultimately though, I have a lot of good data to work with. Clean data, more correctly. There were certainly (many) rides where things went wrong somewhere in steps 1-7, meaning that ride got tossed out. It could be something as simple as the battery dying, or it could be that a unit got inadvertently stopped without me realizing it or that there was some form of ANT+ interference. All of it meant that the ride got tossed from using in this review.
All data shown in this review is prior to the firmware update from approximately two weeks ago. All raw data for this review is available at the end of the review for anyone to download and analyze should they wish.
Some random thoughts before we get started:
Before we dive into the analysis, I want to cover some ground on a few topics briefly. Mostly as a way to ‘catch-up’ folks on various areas of note relevant to this review.
On my pedaling: It’s been funny how some have attempted to identify issues with my riding style during the original review, somehow impacting the tests. Some said I was left-leg heavy (thus impacting things). Some said I was right-leg heavy (more issues). Some said I stopped and started my bicycle the wrong way. Or pedaled the wrong way.
I say this in the nicest possible way: None of that matters. Really, it doesn’t. It’s trying to find fault where fault doesn’t lie. Either the product works with a random cyclist (me), or it doesn’t. Whether it works with a different random cyclist (you), is certainly debatable. I lack the concentration to somehow pedal a certain way for hours on end. Perhaps a professional tour rider does, but for me, I’m just gonna keep on pedaling the same way I have since I had training wheels on. Which based on what I can tell – is probably the same way you pedal. And at the end of the day, it’s all about whether the unit works across the board – yes or no.
On studies of how people peddle: There’s certainly been some interesting studies on how people peddle. I’ve looked at a LOT of studies on this topic. But there’s some key issues that folks like to talk around. First is that most of these studies are 20-30 years old. That doesn’t mean they aren’t useful. But that does call into question the accuracy of the data collection methods on left/right power meters. Keep in mind that it’s last year that we finally got a left/right power meter that works outdoors. Most of the studies are indoor-based, and it’s well proven that power meters act differently indoors than outdoors. Even the more recent ones are very small in their data sets – literally in some cases just a few rides.
Again, I’m not saying to ignore those studies. But I am saying to take them with a boulder-sized grain of salt.
On ‘second/update’ reviews: This is the only time I’ve ever completed a ‘second review’ on a product. Historically when a company prematurely releases a product, they have to live with the reviews published to the internet based on premature release. Ask Motorola how that worked out for the Motoactv. Or Garmin. I often go back and make minor changes or updates based on new features or changed functionality, but not wholesale new reviews. Power meter reviews are actually the most complex reviews I have to publish. They are incredibly tough to get ‘right’, and a lot of data collection and analysis goes into it. Thus, when I publish a second review for a product, that means at least another 2-3 products in The Queue get pushed out further and delayed. That’s the only way it works in a time-constrained system.
On data collection: One aspect that some have wondered whether it impacted the end results was the Edge 510/810 in some of the original tests, which had an issue that resulted in some power drops. Out of curiosity, I looked more closely at this and went and actually ‘nulled’ those drops (they were very predictable timeline-wise in that particular firmware version). However, that still didn’t resolve the core issues brought up in the review around variability. Nulling out the Edge issues only moved things about one half of one percent in most cases (on average it occurred once every 2 minutes). So while it did have an impact, it was sorta like dumping a glass of water into a flooded house.
On differences between power meters: I see a lot of talk about the holy grail of never switching between power meters because it means your data will be offset. That’s true. There’s a fundamental difference in power measurement location between using a crank based power meter and one on a trainer or wheel. No doubt. But I’d argue that in the scope of power meter technology today – it doesn’t matter. I’d argue that most folks don’t calibrate, and even those that do, wouldn’t necessarily know when the data is right or wrong or when a power mis-calibration has occurred. ‘In power meter we trust’. Can you, out on the open road, tell the difference between 5w higher or lower for 4 seconds? How about 10w on an hour long climb? And if you can (which, you might), can you tell me where and when that variation started to occur? And can you do it over the course of multiple years and ensure that ever single ride was calibrated perfectly? And, as you’ll see below – that’s the real question, and not just for the Stages, but for any power meter.
The Tests and Results: Indoor Rides
Let’s dig into a handful of rides. These are rides where all data recording aspects went as planned, thus enabling us to really dig into the data. As with the previous review, any obvious ANT+ transmission errors (i.e. interference) were nulled as to not impact any specific power meter. This is not the same as spikes or drops however, and in the event of those, they were and are specifically called out. ANT+ interference errors are easily seen because they tend to affect all data channels (i.e. heart rate included).
These two rides were done indoors on trainers that have the capacity to both generate resistance as well as measure power. That’s key because it gives us even more data points to work with in some cases (what the resistance ‘should’ be).
90 Minute Indoor Trainer Ride:
This indoor ride was completed on the CompuTrainer (CT), with three additional power meters: The PowerTap, Stages, and Quarq. Per the calibration procedure, each was manually calibrated (or roll down in case of CT) prior to the start of the ride. Then again at the 20 minute marker, all were manually calibrated again. The workout itself was as follows:
A) 10-Minute warm-up
B) Some high-cadence work for 10 minutes
C) (Then Calibration)
D) Building for 15 minutes
E) Then 3 minutes easy
F) 3 x (10 minute intervals with 2 minutes easy in between)
G) 4 x short 30s sprints
H) 5 minute cooldown
With that in mind, let’s look at the overall stacked graph below. This means that the numbers are simply stacked on top of each other. It doesn’t mean that the Quarq is measuring higher. I did this just because for this graph it’s easier to see.
As you can see, the numbers ‘tracked’ quite closely across all units. But as I discussed in the first review, creating a comparative graph isn’t as useful because it tends to ‘skip’ over details, such as the exact variability between units.
Next let’s look at the difference between the power meters in watts. This is somewhat complex to display on a single chart for all units at once, so it’s in multiple charts instead. The titles specify which power meters are being compared. The vertical axis shows wattage, and the vast majority of the ride my average wattage is between 230 and 280w (to give context on percentage).
Note that all charts are sized with a min/max vertical axis of –80w and +80w.
Next is against the CompuTrainer itself. Note that the CompuTrainer has a specified warm-up period of generally between 10 and 20 minutes. Thus why you see the divergence there for those first 20 minutes. It’s not the Stages causing that divergence. Once I complete the secondary calibration on the CompuTrainer, it snaps right into place.
For completeness, here’s the Quarq vs PowerTap numbers. As you can see, any two power meters will differ.
So what do you see above? Well, in all the charts the vast majority of the time you see the difference being less than 20w. You’ll see some spiking towards the end, but that’s in the 500w+ intervals that I was doing, and thus the difference is likely due to lag more than anything else. But remember, we’re not looking at any difference itself as being bad, but rather the variation of the difference. Each power meter measures power in difference places. As a result, the PowerTap will generally show less wattage than the Quarq, for example. So we’re looking to have more of a steady line – wherever that may be (high or low).
In looking closely, you see that in general the variation was lowest when comparing the PowerTap to the Quarq, and the Stages to the CompuTrainer.
But if we step back and look at this graph from the standpoint of a coach, focusing in particular on the three main interval sets – it’s clear that you can easily discern what the athlete is doing, and their output level.
If I look at just the first 10-minute interval for example, here’s the averages:
Quarq: 287w
Stages 278w
PowerTap: 288w
CompuTrainer: 270w
And the second interval:
Quarq: 282w
Stages 274w
PowerTap: 282w
CompuTrainer: 266w
And the third interval:
Quarq: 281w
Stages 269w
PowerTap: 280w
CompuTrainer: 266w
As you can see, any coach could easily use any of those numbers to give perspective feedback to an athlete on how this ride went. In my case, all three intervals were set to essentially the same values at the start, with a slight fade of 10w over the course of the interval (where I backed off the wattage to keep within a HR zone).
What about one of those sprints at the end? Well, here’s what one of those look like (averages including the build/fade):
Quarq: 487w
Stages 458w
PowerTap: 457w
CompuTrainer: 441w
As you can see, there’s a bit more variation, but not much. But which one is right? That’s the tough part. How do you quantify exactly which one is correct? The Stages and PowerTap were only 1w apart.
Now let’s look at total ride averages. As noted once before – that’s the absolute easiest bar to meet. I can put up a $99 PowerCal strap and get pretty close to spot-on averages (within a couple watts). But nonetheless, here they are:
We see that the Quarq is the highest, which is logical – it’s measuring power closest to my legs. And the PowerTap and CompuTrainer are lowest, also logical given their place later in the equation (due to drivetrain loss). We see the stages sits below the Quarq, and in this case slightly below the PowerTap as well. For reference, the difference between the Quarq and the Stages is 4%, whereas the Stages and the PowerTap is 1.5%. And the Stages and the CompuTrainer is less than 1%.
80 Minute Indoor Trainer Ride:
Ok, next up, another indoor trainer ride. The structure was fairly similar as the first one:
A) 10-Minute warm-up
B) (Then Calibration)
C) Some high-cadence work for 10 minutes
D) Building for 15 minutes
E) Then 3 minutes easy
F) 3 x (8 minute intervals with 2 minutes easy in between)
G) 4 x short 30s sprints
H) 5 minute cooldown
With that in mind, let’s look at the overall stacked graph below. Again remember that the stacked graph simply shows all of them on top of each other, thus there will naturally be gaps. It’s used to easily see the differences.
So let’s dive into those differences. Like above, I’ve done ‘difference’ charts pitting the Stages up against each one. Here’s the Quarq vs Stages – difference in watts. In order to keep them inline with the earlier charts, the scale was kept at +/-80w. In the below example it bumped just a touch bit higher in those intervals, at 94w.
So before we move onto the others, you’ll see that in general it’s within 20w the entire time. Again remember that delays in transmission and recording can cause some of the variability. The spikes you see at the ending are due to the quick sprints I was doing. Because of the fact that these were only 20 second sprints at a high intensity (500w+), they can easily produce differences like you see due to that delay.
Here’s it plotted against the KICKR (via ANT+):
And then here’s the Quarq and KICKR plotted. Remember all these graphs are smoothed at 10s (the underlying data is).
You’re probably looking at the above and seeing a lot of variability with the KICKR. And that’s true. Remember that the KICKR measures power based on changes to speed. It’s doing it differently than based on pure strain gauges. What you see above is that during the portions of the workout where I’m shifting speed/cadence/power significantly (the high cadence portions & the sprints), we see variability due to data lag. But in the main sets we see the values very close (less than 10 watts).
Here’s the average/max/NP for the ride:
As we can see, the average and NP numbers were very close. The max watts on the KICKR was a bit lower, but that makes sense because it wouldn’t likely have felt a 1s spike during a sprint as high as the Quarq or Stages. And at 753w, the difference between the Quarq and Stages is exactly 2.5%. Well within the published margin of error for either unit.
The Tests and Results: Outdoor Rides
Now we get to the fun stuff – outdoors! While I have lots of rides in Paris, I’m actually using two particular rides below for a reason. First is that I have the WASP data, which makes it easier and cleaner to visualize. But second is that unlike my Paris rides which are full of stops due to traffic/etc, these are more or less nonstop. Thus making it easier to both visualize as well as spot any differences. With stop/starts of traffic, it can become very difficult to separate out drops/spikes from simple stopping and starting rapidly.
Las Vegas Desert Ride:
This was a ride I did while in Las Vegas in mid-April. First up is the stacked graph. Now, this can be really busy looking – because it’s far more variable outside than inside. The route itself is more or less never-ending rollers. So I’m constantly shifting power according to terrain. Note, you can click on any of these to expand a bit.
So, let’s smooth things out a bit with a 10-second average:
Again, remember these are stacked, and thus not the actual difference between the units – but rather the relative differences in how they track.
Now let’s look at the differences between each one. As with before, these are all smoothed at 10s.
Now for the Stages vs PowerTap:
And finally, Quarq vs PowerTap:
Now, the challenge here continues to be the variance in outdoor data when comparing rides side by side. So I applied a 1-minute (60-second) smoothing to it:
So within this, we can clearly see how they tracked. In most cases they aligned quite well. We see that in general the Quarq tends to ‘rise’ above the rest from a max standpoint, either because it’s measuring further up the drivetrain (likely), or because it catches some of the short bursts a bit better. We see that the Stages pretty much just slides in between the Quarq and the PowerTap and tracks well against both. The only cases where we see differentiation seem to come from the PowerTap on some of the descents – reporting a bit lower power than the rest.
Finally, here’s the totals across all three units:
As you can see, all within the same ballpark. But again, getting ride total averages in the same ballpark is pretty easy in the grand scheme of power meters. What I do appreciate though is that you can start to see a pattern between the Stages, Quarq and PowerTap being developed. We see that the Quarq tends to be the highest numbers (Avg/NP), with the Stages slightly below it, and then the PowerTap beyond that. This likely means that my left leg is just a tiny bit weaker than my right leg, as the Stages is only measuring left-leg. The difference between the PowerTap and Quarq makes sense and is inline with expectations, likely due to drivetrain loss.
Mountain Ride:
This ride was done shortly after the Vegas ride. But now I’d travelled to Los Angeles and this ride was starting right at the base of the nearby Angeles National Forest (basically a mountain range), and then heading up into it. The weather down low and on the climb was miserable (pouring rain, cold), but up top it was beautiful.
I really wanted to include this ride because it shows just how massive the impacts of weather and calibration can be on data. Data that unless you had multiple power meters on your bike, you’d likely not realize there was an error.
First up, let’s look at the stacked graph. Quite frankly, this is a mess to try and decipher– so let’s just move on.
So let’s go ahead and apply a 1-minute smoothing to it. This creates a rolling average of the last 60-seconds of data.
Wow, lots of interesting stuff in there. But before we do that, let me give you the elevation profile of the ride that goes along with this. This is set to display as ‘time’, because that’s the same as above (seconds). I specifically moved the elevation points to the right side of the graph, so that it basically aligns visually to what you see above. Where the numbers are on the right side the mountain just goes back down (I start/end in the same place).
What that in mind, what you see is that there was no place for any auto-zero type technologies to kick in on either the Quarq or the PowerTap. In the case of the PowerTap, that happens while coasting. And in the Quarq, when I backpedal. Since I was literally climbing for nearly an hour straight – the only way to do so would have been to stop and get off my bike.
So I did….
First calibration: You’ll see a manual calibration I did (I marked it on the chart two screenshots above), this was about 15 minutes up the hill, where I literally pulled off to the side and manually calibrated. In doing so, all three PM’s started to align again.
But wait, that didn’t last terribly long. Look below. In yellow highlighter I’ve highlighted the two points where I did a calibration or auto-zero. As I continued to climb, you see the power meters start to drift apart. The stages stays relatively constant, but the Quarq drops off significantly – upwards of 50w+. And the PowerTap even starts to drift downwards as well, about 10-15w.
As soon as I pulled over to a random viewpoint and did an auto-zero coast, they both snapped right back in place.
Why were they drifting? Well likely because of this:
This is the temperature chart for my ride. You can see a 15*F+ shift. Keeping in mind that the Edge 800 temperature gauge (which is what this is from) has the updating speed of a turtle. It would literally take 5-10 minutes to drift from 72*F to 0*F in a freezer. So in reality, the temperature shift is likely closer to 20*F+. Here’s what it looked like outside (it’s pouring):
So how do I know that the PowerTap and Quarq were drifting, and that it wasn’t just the Stages? Well, some if it comes from knowing yourself. In my case my heart rate stayed pretty constant across that timespan. And while heart rate isn’t always a great indicator of power, it does help provide context. I certainly wouldn’t have lost 50-70w in wattage over the course of just an hour climb.
Next is that the Stages contains temperature compensation, whereas the Quarq doesn’t. Also, once the auto-zero was done on the Quarq and PowerTap, everything instantly aligned back to where it should have been. Keep in mind there is no manually triggered auto-zero on the Stages (happens continuously), so there was nothing changed there at that time.
We also see some of this same drifting in reverse (plus a bit of other funkiness) happening to the Quarq on the descents on the way back down.
So, as we look at the ride totals, you’re going to see data different than ‘the norm’. Because the Quarq and PowerTap were measuring low during the climb, these numbers will be lower for average and normalized power. Of course, that doesn’t impact max power, which is across the entire ride. In this case, we do see a fair bit of variation in maximum power – more so than I would have expected, with them each offset about 100w (200w range in total). The challenge with max power though is that it can be one split-second packet that determines it.
So where does this leave us? Well, the Stages appears to have a fairly solid temperature compensation system built into it. The PowerTap didn’t drift significantly in comparison to the Quarq, though we certainly saw that.
Now, when we look at the middle portion of the ride where the temperature was fairly constant, we see that all three units tracked very well against each other:
Excluding the climbing/descending aspects, you could have easily used the middle data from any of those power meters. It’s only when you include the climbing/descents that you reduce the viable units to use for this particular cold and rainy day.
Cadence items of note:
I wanted to briefly cover cadence, though I thought it was pretty well covered in the original review. As you may remember, cadence within the Stages Power Meter does not depend on a cadence magnet, and thus uses an internal accelerometer. This means that there is no magnet installation required, nor any other sensor required on your bike. It just does its thing internally to the pod attached to your crank arm.
Now in the original review people seemed to continually look at the graphs and think that I said there were cadence issues with the unit. Despite clarifying this numerous times, there was still confusion there. What was said at the time was that below 60RPM we saw some impacts on torque (and thus power), but we didn’t see any issues with the cadence itself.
I tested the cadence range down to 30RPM, and up to just under 200RPM – against a known good. In this case that ‘known good’ was a traditional magnet-based cadence sensor. (Fun testing aside, it’s actually interesting to see the Stages PM drop off at precisely 30RPM. 31RPM is good, 30RPM gone.)
Taking a look at an indoor plot first, this is cadence of the Stages cadence vs Bontrager magnet cadence sensor. The graph is the 10-second running average plot, variation shown in RPM. Really do take note of the scale here though.
As you can see the average difference was between 0 and 2RPM. But again, that’s because there’s going to be some reaction time delay there from an electronics standpoint – so even just a single second delay would show up here (delay caused by transmission or recording). Said differently: They look basically spot on.
Now, here’s an outdoor ride (the Vegas one):
In this case you see more variability because of stops and starts being a factor and the data time slice needing to be just 1-2 seconds. So from a post-ride data analysis standpoint, it’s actually relatively difficult to see. To exemplify this, I went ahead and looked at a few of those areas where there’s divergence.
Now, you may be asking ‘Why don’t you just slide the entire data plot a few seconds?’. Well, when I did that it skews off the power. Meaning that while the power aligns fairly well from a timecode standpoint, the cadence does have a slight delay in it. Not enough that you’d notice it out on the ride, but enough that you notice it when you stop pedaling altogether (which is the case above).
It’s one of those things that’s much easier to see when displayed on a head unit because you can look at both units at once and see that even though one might be delayed .5 to 2 seconds, it’s showing effectively the same thing. For example, if I stop pedaling for an intersection. One unit might take 1 second to go from 90RPM to 0RPM, whereas the other might take 2 seconds. Thus on a graph it would look like there’s a ~90RPM gap, when there’s not. They’re both measuring it correctly, it’s just that there’s some internal communications and recording differences.
Again, I’m simply not seeing any issues with cadence on a road bike (nor was I seeing issues before) – either real-time indoors, outdoors, or in analysis afterwards. I don’t have a mountain bike, so I can’t in those circumstances. I do however have plenty of cobbles in Europe though – and saw no issues there.
Pacing and Wattage Stability:
One of the core areas of concern with the previous firmware was the instability of the pace. While power meter users will note that wattage on power meters fluctuates second to second, the initial Stages firmware introduced too much variability in my opinion – even while using smoothing options.
The best way to exemplify this is to simply show it. So I went out and captured some simple steady-state riding down the street. Nothing complex here, just riding on mostly flat ground. There’s no fundamental difference between riding on flat ground or a mountain from a strain gauge standpoint, it’s all just ‘effort’.
Here’s the video clip of steady-state riding. In case it’s not clear, there’s three head units, each labeled with Stages (left), Quarq (right), and PowerTap (top):
As you can see, I included instant power (top), 3-second (3s) power (middle), and 10-second (10s) power (bottom) on the display. All three ebb and flow together pretty much together.
Comparing Bluetooth Smart and ANT+ from the same unit:
After publishing this update earlier this morning a few of you asked about the Bluetooth Smart aspects, specifically focusing on comparing the ANT+ data coming from the Stages unit to the Bluetooth Smart (aka BLE) channel. As background, the Stages Power Meter is the first power meter to offer dual-broadcasting of data across both ANT+ and Bluetooth Smart, ultimately letting the user decide what devices they’re going to connect to the unit.
On the ANT+ side you have all the traditional power meter head units (i.e. Garmin, Timex, CycleOps, etc…). Whereas on the Bluetooth Smart side you have cell phone based applications, today limited to those on iPhone 4s and higher devices, as well as newer iPad/iPod devices with Bluetooth 4.0 in it (which is required for Bluetooth Smart). There is not yet compatibility on either Android or Windows Phone. I dove into the Bluetooth Smart aspects in more detail in the original review.
But I didn’t spend too much time either in the original review or in the update looking at comparative data from the Stages Power Meter when analyzing both data channels at once (ANT+ & BLE). So since I had a longish trainer ride today, it seemed like the perfect opportunity to give it a shot.
The setup for this was relatively simple: I had an Edge 800 recording the Stages ANT+ power stream, and then I had an iPhone 4s with the Wahoo Fitness App recording the Bluetooth Smart stream. I use the Wahoo Fitness app because I feel it’s the most complete app out there for data recording and analysis. It doesn’t have all the ‘community’ features of some other apps, but when it comes to data and getting data in any format on earth with reliability – it rocks that boat.
This then gave me a slew of files. Oh and for fun, I was also recording the PowerTap and Quarq concurrently – but we’ll ignore those for this test (I have included them in an updated set of raw data files however at the end of the review).
After getting all the data consolidated I started by throwing it into a 1-second chart:
Interesting, you do see some interesting variations there between the two plots – which I’ll get to in just a few moments. One track is a bit more ‘tapered’, while the other more volatile. But does it have an impact on segment averages?
Let’s first look at all the segments of my workout from today. Comparing the average wattage and cadence of each segment along the way – some as short as 2 minutes, some as long as 15 minutes. Plus the overall averages and max’s.
Again, near-perfect comparisons doesn’t tend to be exciting. But the above is pretty astounding. It’d be difficult to achieve that even with two Garmin Edge 500’s side by side recording the same power meter. I would expect that because it was a trainer ride, there’s slightly less variability than an outdoor ride – so you might get a hair bit more variation there.
So why are there itty-bitty sub-1% variations (more like sub-.5%)? Well, the Bluetooth Smart channel in this case is updating more frequently. It’s not that ANT+ can’t do that (as in fact, I do it with the WASP units all the time as shown in this review). It’s just that the Garmin doesn’t record higher than once per second. Which means it may miss some stuff. Hence why you see the higher max value on the Bluetooth Smart side – it likely had a split-second sample where I peaked higher than the Garmin even saw. This also means that you see a touch bit smoother track on the Bluetooth Smart side as it’s not just picking one semi-random packet out of the air, but rather grabbing a bunch and averaging those for the ‘1-second’ data point viewable to us.
While this one test shouldn’t be considered the end-all-be-all of accuracy, I did want to include it for those who were curious. It seems to me that the data is pretty darn solid though.
(Again note that this test above is on firmware prior to the latest Bluetooth Smart update, which may address any of the tiny little variances I saw.)
Final Thoughts:
Back in my first review of the Stages Power Meter, I concluded with the following statement.
“At present, based on me (and only me) it would be difficult for me to swap out my existing power meter with the Stages power meter. There’s just too much variance and fluctuations in power. Do I think that Stages can get there though? Yes, I do. But I think it’s going to take time, and likely more software work.” – January 2013
Based on what I’ve seen, they’ve done that work (and put in that time) – into the software. The physical unit I have has not changed since the original review. It’s the same unit I’ve had since the very beginning. They’ve just updated the software within it. And they took a lot of feedback from the original review and addressed issues of concern we had.
For me, I have no issues in using any of the power meters I’ve used in this review – including the Stages. I do in fact from time to time pick different ones, and the data is generally similar enough that there’s no discernable difference. Further, in some situations (such as nonstop climbing with shifts in temperature), the Stages simply performed better than two other units. This likely due to its automatic temperature compensation algorithms.
As for Stages being left-only and doubling the power, for me (and again, just me), I’m just not seeing any issues there. It’s possible that others have larger discrepancies, or that those discrepancies could vary. But in my case it seems pretty consistent across a wide variation of rides and riding conditions.
I think probably the biggest takeaway here is that no particular power meter is perfect. Anyone who says that there is, is sadly mistaken.
Given all that, here’s the updated Pros and Cons table:
Pros:
– Cheapest direct force power meter on market today
– Easy to install. Silly easy.
– Tons of crank compatibility options
– Accelerometer based cadence measurement works really well
– Utilizes standard CR2032 user-replaceable battery
– Automatically compensates for temperature changes
– Lightweight – 20g
Cons:
– Left leg dependent, simply doubles left leg power
– Total power could be highly impacted by your left/right distribution (but I didn’t see this)
– No method of end-user calibration validation (for advanced users)
– Doesn’t support Rotor cranks/arms as of today, or carbon crank arms
Thanks for reading! And as always, feel free to post comments or questions in the comments section below, I’ll be happy to try and answer them as quickly as possible. At the end of the day keep in mind I’m just like any other regular triathlete out there. I write these reviews because I’m inherently a curious person with a technology background (my day job), and thus I try and be as complete as I can. This isn’t my full time job. But, if I’ve missed something or if you spot something that doesn’t quite jive – just let me know and I’ll be happy to get it all sorted out. And lastly, if you felt this review was useful – I always appreciate feedback in the comments below. Thanks!
Finally, I’ve written up a ton of helpful guides around using most of the major fitness devices, which you may find useful in getting started with the devices. These guides are all listed in the ‘How-to’ section. Enjoy!
Note: Raw data files used in this review are available here. Notes are contained within each folder.
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incredible work Ray!
Great scientific analisys, data collection and conclusion.
That’s the way to give the right perspective on this subject, not personal feelings but solid data!
It’s probably not so fun, but I think it would be great if you add this perspective on every PM review you’ll so in the future!
When will they ship outside US/Canada?
They’re aiming for the end of this year or Q1 of 2014.
Have you ever had problems with your ant+ signals not being picked up because too many devices were being used? On my last two trainer rides, I had the Stages power meter, Kurt inRide, TrainerRoad with Ant+ usb, Garmin GSC-10 speed cadence, Garmin HR, inRide BT HR, Garmin 800, Garmin Edge and iPhone inRide app all running at the same time. The inRide picked up fine on the iPhone but the Stages power, Stages cadence would only pick up half the time. The Garmin GSC-10 was also cutting off more than normal though would cut off about 90% of the time. I have no clue why this was happening and my first thought was that maybe too many things were running at once causiing interference. However, this didnt happen the first time I had this set up, only occured in last two setups. Then I just turned off everything and used Stages only and the signals were still not picking up consistently. Case of just some unknown interference, Garmin issue, Stages Issue or am is there something I should look for or do to make the connection stable?
I think you need to clarify. Which are broadcasting and which are receive only? You can have as many receiving devices as you want and there is no chance for there to be interference
Stages power broadcasting to garmin 800 and 500 and dropping 50% of the time on both. Stages cadence broadcasting to 500 and dropping 50%. Garmin speed/cadence broadcasting to trainer road USB, and 800 and dropping 10%. Ant + and BT Heart rate from all devices being picked up 100%. inRide power being picked up 100%.
I got the first one in Australia. I updated the firmware and agree with DC, it works great and you can pace against it just like a powertap etc.
Another excellent review. Thanks.
Just tell all those who choose to criticise you that they are most welcome to do it themselves. I originally wrote a slightly ‘harsher’ suggestion for them….but decided against it. Some people have waaaayyy to much time.
A tip of the hat to you sir! This is what I call commitment and dedication. This is why your blog is so much above others.
Thank you!
Your Cervelo looks like the Enterprise.
All you need now is pointy ears and you must train how to do the vulcanian salute properly.
I can’t believe how UGLY your cockpit looks… but I hate Vision Handles, already told you that. :-)
Lol you’re also losing the right elbow pad AHAAHAHAHAH.
Wow Ray, just wow! You’ve proven again you’re the stuff legends are made of.
This revisit highlights just how much dedication, time and effort is required to do a proper review.
Thanks and looking forward to the next in-depth analysis for whatever pops out of “The Queue”.
Hey Ray – the review is not really relevant to me as I’m not looking at a stages PM (or any other) at the moment as I’ve already got my PM sorted.
BUT, just wanted to say thanks for doing the update and all the work on this – way above the call of duty and exactly the reason I come back here all the time to check your reviews before I buy any sports tech. Absolutely brilliant work.
Cheers
Thanks for all the hard work.
I thought all head units picked up an Ant+ power signal at 1 second intervals and all Ant+ power meters broadcast was also at 1 second intervals (well packets were sent more often but the data inside only was updated once per second. The only power meter that updated the data more often is SRM which updates at 4Hz. Do the power meters change the data they are broadcasting more then once a second meaning there is data lost with what the head units see?
(Based on your power meter primer links from before link to slowtwitch.com)
The SRM is the only one that not only broadcasts but captures at a higher rate. The rate for the others will vary slightly. In the files you can see the current number of packets that it received for each second. Some power meters are just broadcasting duplicates, and some are actual differences. With the current software, the WASP averaging those out. Again, this is unique to the WASP and not something offered today on Garmin devices.
ANT+ Power protocol allows for updates at about 4Hz. As Ray says if the meters use this full capability is up to the meter but generally there are two styles either update at a fixed internal rate or update based on a physical thing e.g. wheel or crank revolution. You can find the spec document on the thisisant site.
I’m a current powertap user, but have always wanted to try the Stages. However, I run different crank lengths on my Road & Tri Bike (172.5 & 165mm). Do you think it is possible to simply stack my Tri shoe to compensate for the length discrepancy (assuming I get a 172.5mm arm and slap it on a 165mm crankset)? Would power numbers be affected?
Is this something you would be interested in testing?
Assuming you’re using shorter cranks on the tri bike to keep the hip angle from becoming too acute (a logical reason), using a 172.5mm arm *and* shimming the cleat will result in an extremely tight hip angle on that side. Even if it doesn’t impact power production, you would seem to be asking for trouble in terms of developing muscular imbalances, perhaps even injury.
Assuming you want to keep using such different crank sizes (if you compete primarily in tri, consider 165 on the road bike as well), maybe pick which bike you want a powermeter on, or buy two.
JBV,
Thanks for the inputs.
Why would the hip angle close in that case? Wouldn’t the net effect simply be the effective crank ‘length’ be 165mm? Is it because at TDC the effective crank length would be 172.5 + 7.5?
Javy, yes, that’s exactly it, at TDC (where hip angle is tightest) you’d effectively be riding a ~180mm crank with the combination of the 172.5 and the shim. Shimming doesn’t shorten the effective crank length, is simply “offsets” it higher.
Sorry for taking a couple days to respond, I hope that helps.
Another great review Ray -Thanks.
I am very interested to see if the prices of other power meters will now go down now that the Stages system has been validated by Ray and they have a credible lower priced competitor..
Thanks again for your thorough reviews.
Have you tried the Stages meter on another receiving device other than the 510/800 Garmin series ?
Yes, I’ve used it on everything from the O-Synce, to the Garmin Edge 500/800 (as well as the 510/810), to the iPhone with ANT+ adapter, to the WASP. It follows the ANT+ power meter standards, so it’ll work with anything that supports the ANT+ power meter spec.
Ray, I see from your photos you have a 510 connected to a powertap. I have yet to be able to connect those two devices. I swapped out the 510 for a replacement model and have the latest firmware on the g3. Did you have trouble connecting. Garmin says they know of the issue and are working on it.
All the devices in this review are Edge 800 devices, with the 810 only used to demonstrate the power steadiness in that one video.
As for issues with the 510 and the PT, I thought it was a pairing issue – meaning it wasn’t surfacing the search correctly, but if you knew the ANT+ ID then you were good to go.
Thank you. Have you (or can you) confirm success with iPhone Bluetooth and/or Garmin 910XT?
The reason I’m asking is that I have purchased one and have only been able to verify solid operation on a Garmin 510 (borrowed) but haven’t bern successful with Bontrager Node 1, Magellan Switch Up, iPhone 5 ( Bluetooth – wahoo fitness ). Stages support has been great to work with and have been very responsive.
My Stages PM works great with my Garmin 500, but will not stay connected to my iphone 5 if I put the phone in a jersey pocket. I think I’d have a better chance if I put the phone on my bars, or perhaps in a seat bag (or in a cellphone holder in a bottle cage).
For those interested in the Bluetooth Smart aspects, I took some time on my flight tonight and analyzed this morning’s ride where I had concurrent recording with the Wahoo App (Bluetooth Smart) and an ANT+ signal (Edge 800). I’ve added a new section just before the conclusion summarizing (in detail of course) those results. I’ve also added the raw files from that ride into the zip file at the end of the review.
I’ve used the Stages since March. I use it paired with my 910xt and sometimes with my edge 800 and I’ve never had any issues. I haven’t even performed the firmware upgrade yet ( need to find someone with a iPhone so I can utilize the Stages app….). it just works, which is a really nice thing.
Stages just issued another update and Wahoo now works great on iPhone 5. I did a long term ride and indoor trainer ride and no drops ( or 0 power ) unless I pressed pause button ( in which case this is expected
Hi,
Thanks for doing this. One quick question, given the positioning would you say this is compatible with RideSense? See photos below for what i’m referring to.
link to blog.tredz.co.uk
link to blog.tredz.co.uk
Thanks in advance, any reply is appreciated!
What do you mean. I have the 2013 tcr advanced sl frame and it works. But if you sync with a garmin head unit, it will sync to whatever you synced first.
So for me I took off my ride sense and synced with stages. So my cadence and power are from stages.
If I sync ride sense after the stages. My speed so theoretically be from ride sense but you won’t be able to utilize cadence unless you have it synced first. But it seems its cleaner in look by syncing and using the stages cadence though.
Thank you for the review! I’m sure stages is gonna get some more business because of this. I hope they thank you!
I had a few questions about power meters and being that I’m new, this may be for newbies.
Question is…it appears that it’s not about trying to purchase the SRM to ensure that we get a good power meter, it’s about how consistent a power meter is over the duration of use.
And that you mentioned that the SRM records at a higher resolution than the others, does it matter to most of us as cycling enthusiasts?
Also, it is it true that the current power meters on the market, not all of them have temperature compsensation algorithms built in? I would think if so, this is a plus for the stages.
Also, speaking toward value, it appears that the stages could be the best bang for the buck power meter.
Also, with the firmware updates, I’m wondering are you using the latest firmware update or was this before the most recent one (I think last week at the begininng/middle of June 2013).
How important is it for training knowing right and left balance compared to just a left crank power reading?
Thanks once again!
I would like to see if the differences shown in this review also appear with the SRM power meter, which is known to be the “gold standard of the industry”.
That would show if the huge difference in prices represent a huge difference in the data reliability.
Excellent update Ray. I just ordered one for my Cruzbike Vendetta.
The KICKR comparison was good to see as I have one of those too and have been wanting to start working with power on the road.
-Eric
Anyone care to guess who designed the kickr?
Great review! Thank you for your tireless number crunching. I think the real question now is whether or not you will be using it?
Did quarq add temp compensation after you bought the device used in this comparison? They claim to have it in their FAQ:
link to quarq.com
Do Quarq power meters feature temperature compensation?
Quarq power meters are highly engineered and feature multiple temperature compensation systems. From the intrinsically balanced strain gauge arrangement to clever measurement circuit design, temperature effects are isolated and eliminated at every step in the system.
I think quarq are very careful in that statement – Reading between the lines I think they have tried to engineer out problems with temperature variation….not actually include a formal temperature compensation system that actually measures the temperature.
Ray, thank you for your dedication in providing this updated review. I have no particular vested interest other than a shared fascination with data and accurate interpretation. I admire your magnificent efforts.
Excellent review, Ray. Appreciate you digging as deeply as you do. It would be interesting to see how the Stages performs on a Mountain Bike ride, where the variability of cadence and power is very large.
Thanks again!
I don’t even have a bike and read through the whole review! LOL. You are a true techno geek. Great job. I applaud your dedication.
Great review followup. I received my Cannondale SISL2 stages unit last week. I was shocked how light it actually is. Mine weighed in at 13 grams with the battery installed, 7 under the already ridiculous 20g listed weight.
There was question above about Bluetooth connectivity. More specifically, have you used the Wahoo fitness app in Bluetooth mode? Have you had a chance to compare data capture between an iPhone in Bluetooth versus a Garmin with ANT+? Any difference in the data stream or variability?
Thanks for an awesome job!
I didn’t focus on the BLE portion as much, instead focusing mostly on the ANT+ piece. That said, I did actually do it on my 70min trainer ride today (BLE to the Wahoo App, plus concurrent ANT+ to an Edge 800). I did realize though it isn’t inclusive of the update two weeks ago.
I’m just jumping on a place in three minutes (for 8 hours), so I’ll hack at the data on the flight. But, if it’s looking wonky, I’ll redo with the two-week old firmware version (which is said to address some BLE issues).
Ray, on your updated ANT+ vs BLE chart at about 571 on the x-axis there is a flat spot for BLE watts while ANT+ is showing some variances. Any idea what that is and if it might represent some of the comments about folks losing BLE signal for a bit?
Yes, that was specifically the spot I was talking about there. What’s sorta interesting is that there’s two tiny variations there on the BLE side. Again, this was on the firmware pre-BLE update, so it’s plausible that’s one of the areas addressed there.
What’s funny is just how close that section still came out – likely because it was constant power anyway.
I wanted to include it sooner just to give folks some context on it in the larger scheme of things.
I’ve got a Stages arm on a Salsa Mukluk fatbike. I rode it for 1:45 a couple days ago on some fairly bumpy singletrack. The bike has no suspension other than big fluffy tires and I’m 210 pounds in gear. Was averaging just over 8MPH.
My data shows five “impossible” cadence bounces (150-202RPMs) over that time.
Other than that, the data is exactly what I would expect given the ride and how I felt in terms of the power it showed. This is the only sane way to get power on a fatbike right now (some have modified PowerTaps to work, but that’s far from trivial). I also have MTBs with Quarq and SRM powermeters and a PowerTap on my road bike, so I’ve got a pretty good idea what my power should be, anyway.
So the cadence issue isn’t fully fixed yet, but it’s not horrible, either. At least not in my situation. I’d like to see it fixed, but certainly have some lenience on this one.
–Donnie
Yeah, I believe they are still working on mountain bike related issues. Unfortunately as noted I lack such a bike anymore, and aren’t able to give that its due.
That’s an absolutely brilliant test: the completeness and critical attention you bring to these tests makes so many other tests look silly.
One question, however, about the mountain ride: the Quarq is clearly doing poorly. The effect of the re-zeroing seals that deal. But the Powertap appears to barely shift relative to the Stages during re-zeroing. That leads me to suspect the issue with these two was a shift in L-R balance, not a systematic error in the PowerTap.
Shifts in L-R balance with terrain (intertia), cadence, and fatigue are expected.
The net result is it seems Stages has gotten its act together and while a 2% accuracy claim was never possible due to pedal asymmetry, at least cadence is improved and it’s likely sufficient for pacing of efforts within a ride, if not for determination of small changes in fitness over time due to the L-R balance confounding factor. It’s also clear that I don’t regret using a Powertap versus a Quarq.
Hi Dan-
It’s an interesting question. The aspect that still has me believe the PowerTap shifted slightly was that after I broke out of the fog/rain and into the sun (where the temp was relatively stable), future climbs (since most of the ride was climbing it seemed) were much closer again (after auto-zero would have kicked in on some short descents).
What models of each of the PowerMeters are you using? ie. Which Quarq? Which PT?
By the way, forgot to mention that the review, for me, was riveting and very educational. You discuss many of the proper operating procedures and other things we need to be aware of (temp, cadence, PM corelation) when gathering data, racing, or just enjoying the ride. Thank you so much for the informaiton. I plan on sending this link to serveral friends that have powermeters for their general knowledge.
This was a PowerTap G3, and a Quarq Cinqo (original).
I didn’t read through the review in detail so it might be mentioned but were you using one of the new Quarq units with Omnical?
There’s a picture of the bike with the Quarq on [url=https://www.dcrainmaker.com/2013/04/rockslide-angeles-aerodynamic.html]this blog post[/url]. I don’t know if you can tell that’s Omnical or not, but it looks like an older model to me (I am not sure, however).
No, this was an original Quarq.
Another CON might be…. No bb30 Sram Road option yet! Otherwise Id consider getting one!
I’m in the same boat. If they had an affordable option for bb30 I’d be in line to get one.
Cannondale would be your best SRAM compatible BB30 option that stages supports.
Ray,
You rock. Just wanted to say thanks for investing the time to do the comparative analysis. Recently bought an Argon 18 Gallium Pro with the Stages unit in an Ultegra crankset. I’ve paired it w/a Garmin 310xt head unit. After updating the Stages and Garmin firmware a couple weeks ago, data is looking consistent with few drops. I’ve set the Garmin to nix zeros and do the smart recording and that seems to help as well. Thanks again for the great analysis
Would you find any benefit from a virtual elevation plot, as proposed by dr. Chung in the Power Meter 201 article? Could the difference be due to temp. compensation?
Thank you for giving Stages more consideration. Now there’s another PM to consider.
Really hard to understand that level of drift from the Quarq. 50 watts is over 150 offset counts at 90 rpm. I have never seen my Quarq move more than 20 counts due to temperature ( and I’m in Canada where inside vs outside temps on a late fall day can be 50 F deg or more) . It’s too bad you did an autozero instead of a “calibrate” command to see what the actual offset numbers were. In fact, did you do a calibrate before or after the ride? Did the offset numbers change that much? Because if a Quarq changes by more than 50 counts, Quarq will say that the crank is “broken”.
Hi Bob-
Note, I manual zero’d twice during that ride. As noted, once at 0min, and again at 15min. While another manual reset would have been interesting from a numbers standpoint, at that point in my ride an auto-zero seemed to put it back in check (temporarily anyway).
This is actually an area that spawned an interesting conversation amongst myself, Garmin, O-Synce and the ANT+ guys (this very ride). The idea of recording the offset values in the .FIT. O-Synce has seemingly taken the lead there and is already working with both the ANT+ folks as well as a number of the power meter companies on accomplishing this. Good stuff.
This was really the one rare circumstance where I’ve seen anything like this from a Quarq.
I apologize if this has been answered somewhere else but I was wondering if it’s possible to designate the cadence signal from a Garmin GSC-10 as primary over the Stages PM? I use a Garmin Edge 800 and already use the GSC-10 for cadence and back up speed. So ideally I would think it would be better to use the GSC-10 so that any data drops would not include cadence information.
After looking through the Garmin Support pages, I found the following FAQ which appears to answer my question, although with reference to a PowerTap rather than a Stages. I presume the answer would be the same for a Stages. From the Garmin site:
Will my cadence reading be derived from my PowerTap Power Meter or from the GSC 10 Sensor?
Email this Answer
Print this Answer
01/14/2013
When using an Edge 810, 800, 705, 510 or 500 that is paired up to a PowerTap power meter and a Garmin Speed/Cadence bike sensor (GSC 10), it may be noted that both accessories are capable of transmitting cadence.
When using a PowerTap hub and a GSC 10 sensor at the same time, the Edge devices will report cadence through the GSC 10 sensor. However, if the GSC 10 sensor is not present, cadence will be reported through the PowerTap hub.
Reference Links:
PowerTap – link to cycleops.com
GSC 10 – link to buy.garmin.com
Based on what i just tested, if you have a GSC-10 and its magnet attached to the crank arm, Garmin Edge 800 (not sure about others) takes the cadence reading from the GSC-10. During my initial test, i had the magnet attached to the crank arm. The Edge 800 was able to pick up cadence reading lower than 30 (i went as low as 25). In the second test, i removed the magnet from the crank arm and i pedaled at the same low cadence. The Edge 800 was not able to pick up any cadence lower than 30. This meant it was using the cadence reading from the Stages power meter.
One thing i am not sure of is if i have the magnet attached to the crank arm and the cadence is higher than 30, would the Edge 800 be picking up the cadence reading from the GSC-10 or the Stages power meter.
Based on what I’ve read (and posted above) from Garmin, I would have to say that as long as the magnet sensor is in place then it is the primary cadence signal. Garmin has indicated that the same applies to speed as well. As long as you have the wheel magnet in place, speed is determined by the magnet rather than by GPS (Edge 800 at least).
Thank you Changren for that information, it precisely answered my question, and for me, is the last issue I had before making a Stages purchase.
Good stuff, nice test. Another way to always quickly and easily test where power/cadence is coming from is just to unclip the left leg and right-leg peddle. The Stages will instantly drop power/cadence if no torque is applied to the left-leg (as demonstrated in the original review). It’s an easy way to validate things around connectivity. :)
As for pros and cons of GSC-10 over Stages, the main one I could think of based on what I’ve seen is actually just one-legged drills. I’m just not seeing it as an issue in normal cadence ranges (basically anything above 30RPM) with the Stages.
And in fact, on benefit of the Stages cadence over a GSC-10 is that if your GSC-10 gets bonked out of alignment, you’ll drop cadence, whereas the Stages can’t really get bonked out of alignment. This is somewhat rare, but it tends to happen about 2-3 times a year for me (getting bumped).
Something happened yesterday during my ride that made me rethink if when both GSC-10 and Stages Power Meter are present, whether the Edge 800 would default to GSC-10 for cadence. For some unknown reason, i was getting a lot of power drops. Immediately when the power dropped, the cadence went to zero. The cadence would go to zero every single time the power dropped. During some of the extended power drop periods, i noticed that eventually, Edge 800 would pick up cadence, i assume from GSC-10 as power was still zero (or two dashes).
This seemed to imply that Edge 800 is picking up cadence from Stages Power Meter even when GSC-10 is present.
Does anyone know whether Stages Power Meter would send a battery low message to the bike computer? I am wondering if the numerous power drops i experienced yesterday was an indication that i need to replace the battery.
According to the Stages support personnel i talked to, even when a bike computer detects a separate cadence/speed sensor, like the Garmin GSC-10, it will only take the cadence reading from the Stages Power Meter. Based on my experience, i have to say what he told me is true.
Regarding the frequent power/cadence drops that was happening to me the past few days, the Stages support personnel told me it may be due to ANT+ interference from other devices. His suggestion was to unpair all devices and then manually pair up the Stages power meter first (by manually entering its device ID). After that, manually pair up with other devices. I went for a very short ride and so far i have not seen any power drop yet. I will find out on my longer commute home if that is still the case.
Is there a discernible difference between carbon and alloy crank arms? I have a SRAM red crank currently
A few grams. I have a Rival 175mm arm with the Stages unit on it. I can’t compare to Red, but it weighs 35g more than the Force arm I replace on the bike.
I just ordered my Rival Stages PM b/c the weight difference is so small between it and my 2013 Sram Force Crank. It’s only one side too.
Just received a SRAM Rival (175) GXP Stages power meter today. It weighs 240g. The SRAM Red Exogram crank arm (with a Garmin GSC-10 magnet still attached) i removed weighs 150g.
If I could make one suggestion – it would be helpful if you could stick to one colour per powermeter across all the graphs rather than switching around.
Apart from that – nicely done.
You are awesome. Thanks for all the hard work.
Wow, great effort, thank you Ray! Most interesting revelation here is the impact of temperature compensation; here in SF Bay Area most of my rides have large temperature changes over sustained climbs (e.g. 79F to 61F over 45 min / 7 miles two weeks ago, 77F to 62F over 47 min / 8 miles couple of days ago). For riders in areas of strong microclimates, the Stages may have quite an advantage. I have had my Stages since beginning of March and aside from a few 1-2 sec power spikes earlier (none with the latest firmware), the data has been consistent from ride to ride and matching my “sensations”.
Fantastic Ray, as ever! Thank you!
On the CompuTrainer, in your opinion what is the best way to warm-up the CT that gives a stable cal. number. I have found that after some intervals, I tend to do another cal. spin up, and the number could be out by 2-3 points. Initially its stable with my PT but then I see it drift sometimes. Its definitely not a faulty CT, as I see the same thing with my 2nd CT.
Thanks
Funny, someone just asked this yesterday via e-mail. Here’s my standard CompuTrainer calibration ‘approach’:
1) Tighten screw/knob until I can hold the flywheel (blue thing) and then if I try and move the wheel, it won’t budge.
2) Then on the handlebar unit go into calibration mode (two buttons at once), and spin up to 25MPH and let it coast until it flashes a new number
3) If the number is at ~2.5 (cold, pre-ride), then it’ll ‘drift’ to about 2.0 by time you finish a 10-20 minute warmup. If the number is anything beyond that, reduce resistance and repeat. If already warmed up, then you’re (officially) aiming for 1.8 to 2.2. For reviews I aim for 2.00.
4) Press set to confirm
5) It should now show the new calibration value.
I used to do 10 minutes warm-up on the CompuTrainer, but I found (as part of these reviews actually) that I was still seeing drift. 15 minutes is pretty good, but 20 minutes solved it entirely. My workouts essentially include a 10-minute warm-up (for me), then a 10 minute cadence drill section. So I’ve been doing it after both sections for reviews.
Hi Ray! Great review although i can hardly understand. I don’t have a powermeter and is looking to buy my first one, and of course, the stages one seems to do less damage to the wallet, especially me being a student. I don’t exactly understand powermeter. I would like to ask you how oval and non-circle chainrings like the osymetric will affect the crank based powermeters. It was mentioned in the slowtwitch article (link: link to slowtwitch.com) but i don’t quite understand it. Maybe you could explain it in simpler terms or in other words, make it idiot-proof. Adding on, what can be done to minimize or completely remove this effect if say the effect of the non-circle chainrings are negative. Thanks!
For troubleshooting purpose, i think it may be better to have a separate device (like the Garmin GSC-10) that captures cadence.
I went on my first ride this morning with the power meter and i did not have the GSC-10 magnet on the crank arm. At one point during the initial part of my ride, i noticed there was a cadence drop for a 10-second portion (as validated later via Garmin Connect and Strava). Since this is my first ride with the power meter, i’m not exactly sure what caused it. The power meter has the latest firmware.
If Garmin GSC-10 was providing cadence data, i would be able to have a more concrete proof to show that Stages power meter was suffering from power drops.
The Garmin GSC-10 is not perfect. Occasionally when i ride over the University Bridge (a mostly metal drawbridge), i would get cadence drops until i’m on the concrete part of the bridge. But just for narrowing down the power drops issue, i think i’ll put the crank arm magnet on.
Chris, this explanation might help a little:
link to bikeblather.blogspot.com
In short, any PM that looks at cadence as the average rotational speed over a single pedal cycle (which I believe includes the Stages since it’s accel is looking at peaks in the signal formed by the gravity vector and looking at the time between peaks) will suffer from artificial power inflation.
On my return route, the same portion of my route that had a cadence drop this morning also had cadence drop. Looks like whatever that’s causing the cadence drop is environmental. Since Garmin’s GSC-10 also suffers from similar cadence drop at the same spot, i don’t think installing the crank arm magnet will do me any good. Apparently, cadence sensors don’t like metal bridges :)
Ray, what would be the advantage, if any, of using cadence provided by the Garmin GSC-10 over the Stages power meter?
Hey Ray,
Great review – thanks for taking such care and time to throw down all the information anyone could possibly digest.
Curious, just to think comparatively, how you would weigh the Power2Max vs. the Stages for a new power user? I know thoughts on brands of powermeters tend to be rather dogmatic, but I thought I’d throw this out there for you (or anyone else) to chime in on.
Cheers,
Pat
I think you wouldn’t really go wrong with either at this point to be honest. They both have temp compensation in them, the P2M does have emulated left/right balance (though they will be the first to admin it’s sorta useless in the grand scheme of things). The Stages has BLE + ANT+, the P2M doesn’t. The P2M would be inclusive of any left/right inbalances though.
Price-wise the P2M will cost more, but you’ll have more flexibility there from a bike component standpoint.
In other words, it all comes down to what requirements you have.
I have had my Quarq S2275 replaced 5 times, no jokes “5” times, one of them only lasted 2 weeks. Do you think it has anything to do with them being discontinued, i’m willing to bet money on it.
So comment no 36 ” Quarq power meters are highly engineered and feature multiple temperature compensation systems. From the intrinsically balanced strain gauge arrangement to clever measurement circuit design, temperature effects are isolated and eliminated at every step in the system” that’s a big statement. I believe the Quarq mtb unit has a design flaw and is leaking water or moisture into it.
I’m definitely going to try the Stages, infact I just ordered it. Lets be honest most of us non pro athletes want to use power meters to track fitness, freshness and form so if the average power readings are consistent using the same device then this is what matters.
Ray great, great review.
Hey, great review.
For such mental number crunching in future a stats program like ‘R’ might be useful – it’s a bit user unfriendly at first but is incredibly capable at handling massive data sets. Would easily calculate the deviations between individual units.
Mark
Yeah, ultimately I want to be able to standardize everything a bit more – since PM reviews will only become more frequent.
Today I use some semi-standardized Excel sheets. But I’d like to just get the data into databases and then have a front-end reporting mechanism to make it easier for me to generate the reports (addressing things like coloring even). It’s on the list for the summer (though, my list is growing day by day…).
Your dedication to both cycling and scientific method is awesome.
You should really have a look at http://www.tableausoftware.com
No, I don’t work for them, I use their software for my business and it saves a huge amount of time over charting and data visualisation in Excel, and it’s incredibly easy to publish. Have a look at their gallery. It’s expensive software but
1) you can download a free eval copy of the desktop software, good for a month
2) Tableau Public allows you to use the whole thing permanently for free so long as you publish up your work (which you do anyway).
Like anything it takes a bit of learning but there are good video tutorials and community forums, and given what you can do in Excel this will be child’s play after a few days.
Good luck.
That actually looks pretty cool. The one challenge I have is getting the data from the various fitness file formats (primarily just .FIT these days) into CSV-type formats. Once there’s it’s much easier.
And while it’s a relatively easy step through Golden Cheetah, it’s still a step (import in, change some settings, export out, etc…). I would love to be able to just drag and drop 4 .FIT files from the four units (or a WASP file) into the software and have it ask for which units were which. Then I’d be thrilled.
Hi Ray, what tool are you using to convert .FIT and .TCX files to .CSV?
Golden Cheetah. It’s free and quick.
Neat little cross-post on BSNYC today; nice.
bikesnobnyc.blogspot.com/2013/06/in-xanadu-did-kubla-khana-stately.html
I think we should get a little race together with you, BSNYC, and FatCyclist. I’m pretty sure you’d tear both of them to pieces…
Even funnier since I’m in NYC today…
Ray, i know your preference is to have zero-recording enabled on cadence. I understand why zero-recording should be enabled on power but does having the zero-recording disabled on cadence have any effect on power?
None that I’m aware of.
Never quite understood why you would ever have zero-recording of cadence enabled. Power is obvious as you are resting while coasting, so averaging in zeros makes sense. But for cadence, I want to know that I spent most of my time at 95 rpm, not that when I ride up a mountain 10% pass and then coast down the back side my average is 60 rpm. So what purpose does averaging in zero cadence have?
Is Stages still offering complete cannondale cranks? I can’t find them on their webpage.
Yet another amazing review Ray! As an analyst I definitely appreciate the rigor that you apply to your reviews.
Quick question: It sounds like it is critical to stay up to date with the latest firmware in this product, which then begs the question as to how you actually go about doing that? On the Stages website they provide a link to an iPhone app, but what about us PC and/or Windows Smartphone users?
Nothing for Windows, Android, or otherwise. Essentially you’ve just gotta find a friend with an iDevice. Which, I suppose given how rare you’d need to do a firmware upgrade, that’s not horrible or hard to find.
The challenge is the other platforms have very limited support for Bluetooth Smart, extremely limited. That said, ultimately they’ll need to find a way to offer updates for other platforms, as long term requiring an iDevice isn’t really realistic.
And we now go back to waiting for the Vector for yet another PM review….
Was wondering if you might post/email me a copy of the excel sheet… As a dev with some time on my hands, would love to be helpful, and make an easy auto convert script so you don’t have to manually do the graphs and such for comparison, down the road.
Yup, I’ll send it over later today. Most of what I use is in the raw files, but I have some separate spreadsheets for the graphs/etc… Thanks!
Great work Ray – thank you.
Are you planning to evaluate against the SRM unit anytime soon?
– David
I don’t plan to at this point. Mostly as I’m not sure that would gain anything. Both the PowerTap and Quarq are more than capable power meters on the market today (excluding any minor blips seen above). SRM units aren’t immune to blips either, as every power meter has their oddities (in fact, the Slowtwitch guys showed some of those SRM blips).
Hi – quick question. Do you know if it will be compatible with SRM’s power control 7. On tech specs, it should but a few internet user suggests otherwise. I want to keep all my training files in one software if possible.
Hi John-
I checked with the Stages guys on this. Here’s what they said:
“We are not cross-compatible with the current SRM PC7. As I understand it, they use a proprietary variation of the ANT power transmission protocol that relies on crank torque frequency, which we don’t provide in our data packs. Unless SRM has changed their firmware to receive event based power via the ANT+ standard.”
I would love to see an article ‘dummies guide to calibrating a powermeter’.
I have a powerbeam (which I have only figured out how to calibrate the resistance unit, never the actual power meter which I understand to be different – and then only with the Joule 3.0 included)
I also have a powertap on my racing wheels but in my most recent race it was TOTALLY off. I use it with a Garmin 910
And I just got a stages for my cross bike – also to be used with the garmin.
I have never read a really good overview of why, how, how often etc.. to calibrate powermeters.
Thank you for your blog – its great
Philip
It’s actually something I’m working on – sorta the Bible of Power Meter Configuration advice.. I’ve got most of it written up, but will then be sending all the pieces to the various power meter companies just to validate it.
Guessing you’ll include the difference between selecting the calibrate option on the garmin and backpedaling on the quark or coasting on the powertap? (along with how long you have to coast, I’ve heard it was 5 seconds)
Any chance you could include what to expect when the battery runs low? I know my powertap elite on the Edge 705 just starts dropping power and then stops broadcasting but I thought some head unit and power meter combinations give a low battery warning. Thanks
Eli, my Stages battery just died yesterday. It was after a long commute in the rain and after hearing some issues with waterproofing I was fearing the worst….but luckily a quick swap a roo with a new cr2032 and I’m back in action. FYI, there was no low battery indication from the Stages to my 910xt warning me of a low battery, it just stopped transmitting data.
Gunnar,
Stages advertises about 200 hours on the battery life, do you feel like you got reasonably close to that on your battery? Just curious so I know when to start carrying an extra battery with me.
Gunnar,
Stages advertises about 200 hours on the battery life, do you feel like you got reasonably close to that on your battery? Just curious so I know when to start carrying an extra battery with me. Thank you.
Gunnar, Stages advertises about 200 hours on the battery life, do you feel like you got reasonably close to that on your battery? Just curious so I know when to start carrying an extra battery with me. Thank you.
Eli – Yes, I include both ‘types’.
I hadn’t thought about battery, but will look at appending.
Grif:
Regarding battery life. My very unscientific thought is that the cr2032 battery does probably come close to the advertised 200 hrs. FYI, its super easy to replace the battery. The compartment has a simple spring latch to open. Considering the size, weight and cost of a cr2032, it would be easy to throw one in your saddle bag if you were worried about losing power data on a ride.
Question. Stages doesn’t support Rotor cranks, but does it work with them? Great reviews, Ray, Thank you!
Thanks for the great review! Is the Sram Rival crank you used a good quality crank? I’d be replacing an FSA Gossamer.
Thank you!
Frankly, other than the weight, i can’t tell the difference between my SRAM Red exogram crank arm and the SRAM Rival crank arm. On my rainy day bike, i have the FSA Gossamer. I don’t know how much it weighs but the SRAM Rival crank arm with Stages power meter weighs 240g. In comparison, the carbon SRAM Red exogram crank arm (with a Garmin cadence magnet) weighs 150g.
Regarding the weight diff. of Rival vs. Red exogram…when I switched from Shimano alloy crank to Sram Red exogram I did notice the reduction in rotation weight. Although 90g. isn’t a lot in terms of static weight it is significant in terms of rotational weight. Too bad the stages isn’t carbon crank compatible.
Rainmaker- any chance you could post a graph using 5-min. smoothing similar to what you posted in your original review? Thanks.
Ray: when I read your description about the rigamarole you went through on each ride, calibrating, simultaneously starting and maintaining and monitoring 3 separate power meters mounted on your bike, I just about fell on the floor laughing with the mental image! I’m surprised you’re still alive — distraction related accidents would have been a real possibility. I kept on waiting for an auto impact to end your rider’s point of view demonstration video (Road Runner Cartoon style). Brilliant review, with, if at all possible, more than your usual excruciating attention to detail. I read it twice, and ended up understanding way more about power meters and power output metrics than I knew before.
I know this was not the manufacturer’s original intent, but now they have upgraded their product to be a highly respectable player with reliability, accuracy and precision to spare, impressive temperature correction etc. at a relatively low price, do you see a possibility that some users might want a further development of the product to be also mounted on the drive side, giving a true 2 channel (L and R) power reading? I know there is a lot of skepticism on the usefulness of this metric, but some respected voices in the cycling world still think this is useful information. (I think there is even more useful information to be gleaned from instantaneous power sampling at several specific angular positions in the foot peddling cycle, but that’s another topic.)
FYI: I wrote to Stages to see if they had any plans to release a Campagnolo UltraTorque version of this unit. They were prompt to reply that, while it’s not in the immediate timeframe, they hope to have one at some point.
That’s great for this person whose bike (due to a mechanic’s goof) is stuck using UltraTorque cranks (and I do love said system, far more than I liked SRAM/Truvativ’s GXP).
Regarding UltraTorque, does this mean that we might see the system implemented on a carbon crank? To my knowledge the UltraTorque axle is only available on a carbon crank. I’d love to see the system on a Sram Red crank. Is this even possible and does it just take R&D time?
you would be a prime candidate for google glass :)
Its funny that you found the temp variation with the Quarq… I live in Florida, so even in the winter we get HUGE temp/humidity variations and the Quarq goes off 20-30w. I usually recalibrate right before I start my interval session to make sure theyre as close to accurate as possible. +/-10% is huge, but if its a known issue, we can overcome it.
Thanks for the indepth review. Ive been strongly considering a Stages for my mountain bike, and one for my wifes bike. I think I may be sold now.
If the left/right balance is not as big a deal as some people think I wonder if this sets the stage for some other new PMs to offer a cheaper option.
Vector (while probably dead) or the Brim Bros Zone being pedal and shoe based respectively might be able to offer a single, or dual, solution for 2 different price points. If we could get into the $500 price point I think you would see a lot more people getting PMs.
A new power meter without user calibration needs?:
link to bikeradar.com
I’ve been chatting with them a bit – looking to check it out in person at some point in the next few weeks.
those are good news!!
Hi Ray,
I know this is a bit offtopic, but can you tell me which software do you use for smoothing power graphs? Could you briefly describe how to do it?
I’d be interested in overlaying my power data on top of video, but the raw data is too jumpy and makes it hard to follow.
It’s all just Excel (unfortunately). I just do a running average over a given timeframe (i.e. 60s). So from a formula standpoint it’d simply be: =average(D1:D61) – and then increment the cell numbers by 1 for each new second.
Hi Ray,
Do you know if it’s possible for the Stages Power Meter to simultaneously send power data via ANT+ and Bluetooth to two separate head units? In my case, it would be the Edge 800 and iPhone 5. The reason why i want to do this is because there’s a section on the University Bridge that i have been getting power/cadence drops and i want to see if the drop is due to interference with ANT+. My Garmin GSC-10 suffers from cadence drop (though curiously not speed) at around the same spot as well, but my Garmin ANT+ HR monitor has no such problem. I tested the Stages Power Meter and GSC-10 with my wife’s Edge 500 and at the same location, i get power/cadence drop. So this problem appears to be independent of different models of Garmin-branded head units.
On a couple of occasions when i had my 800 and Strava app running on my iPhone 5, the Strava app would only gather power data for very short duration, like 2 minutes. I don’t have a mount for my iphone 5 so when i did these tests, it’s stored in my backpack. So it’s possible the screenlock kicked in and turned off the display which affected the Strava app. I had also tested this with the mapmyride app, which has an option to prevent the screen from being put to sleep, and even though it appears to be paired up with the Stages Power Meter, it recorded no power data.
I have also tested by just running the Strava app alone (again stored in my backpack) but it actually didn’t record any power data!
Stages have missed a trick here with their pricing. The cheapest Stages is $699. Why would anyone buy a Stages power meter at a price point where they could buy a used Powertap Pro+ – an established, tried and tested tool?
Stages should have come in at $500. Perhaps they could cut the price by selling the power meter only (without the crank arm) and allow the buyer to fit it? They would capture the market for cheap power meters.
For someone with multiple sets of wheels, PowerTap is not a viable solution unless you are willing to pay for just as many PowerTap hubs.
As for selling the power meter only without the crank arm, i think this will be difficult. I am guessing the Stages power meters have to be attached to the exact same location on each crank arm to have accurate power readings. The strain gauges in the power meter may record different values if the power meter is positioned on other locations on the crank arm. The formula used to calculate power will most likely be different if the power meter is placed closer to the pedal than closer to the bottom bracker.
The other challenge is a number of people don’t like buying power meters used, especially if they then require sending somewhere else to validate calibration.
How on earth do you find the time for a day job, training for tri’s and writing these ridiculously detailed educational seminars? Damn, well done! It appears the mtn bike version still needs a little work, but I am sold for next year.
Long nights and weekends…
Incredible review! Thanks for taking the time to put this together. Stages sounds like a good Christmas present for me
Just installed my Stages Power meter, updated the firmware and noticed power/cadence drops when my Garmin 800 is on the Barfly which sits outward directly in front of handlebar. At first I thought I received a defective product, but when I put my garmin 800 on top of stem or on top of habdlebar, there is no power drop to 0 watts.
I am thinking the line of sight for the ANT+ reception is blocked by handlebar/stem when on the Barfly, but not when on the stem for some strange reason.
Also, I have no drops when I am using my Iphone Bluetooth connection (Doesn’t matter if blocked by bar or stem). I will be giving Stages a call Monday just to confirm.
Ray, when you were testing the Stages Power Meter, did you experience any occasional spikes in both power and cadence? Since i bought my Stages Power Meter (with the latest firmware) in mid June, i have seen power/cadence spikes in four rides. They typically do not last more than a few seconds and they range from low 1000 W to close to 2400 W! The unusual thing i noticed is that even though the cadence is supposed to be provided by a Garmin GSC-10, during those power spikes, the cadence went up as well. It is as though the Edge 800 was ignoring the cadence reading from the GSC-10 and chose to get its cadence from the Stages Power Meter. During the power spikes, the cadence went as high as 183 RPM.
No, not since the new firmware updates. I did see it way back when in the original firmware installation (an issue that did come up at the time in my review), but not since. Hit up the Stages folks on that, I know they would be highly interested in hearing/seeing it.
Changren, was this on the road or a mountain bike? If MTB, any chance the spikes correlate to hitting the ground with a pedal/crankarm? I’ve had a few high cadence spikes, but only on the MTB and I *think* they came when I hit the ground.
–Donnie
@Ray: Thanks. I have just sent off an email to the Stages folks.
@Donnie: This was on my road bike.
Is anyone else having power drops while using the Garmin out front mount or the BarFly mount or the K-Edge Garmin mount?
Any chance your using a FR910XT? If so, be sure to be on semi recent firmware. If not, can’t help there too much. I’m using the Barfly TT mount without issue with the Stages.
I have a Garmin out front mount with an Edge 800. The only time i get power/cadence drops is when i ride over a section of a draw bridge near my house. The same power/cadence drops happened to an Edge 500 mounted on the stem as well when riding over the same section of the bridge.
Iv’e tried both an 800 and 500 on a BarFly and both power drop.. New battery ,and updated firmware.. No power drops when mounted on top of handlebar on left side while climbing. When mounted on stem, I got a power drop after 15 minutes.
Update: I called Stages this morning and they said it’s most likely an antenna ant+ problem so they will be sending me out a replacement today. Efficient service.
i’m seeing this with my 910XT on the latest firmware but not the Edge 800. Good to know they know of the issue. I’ll ring them up and see about a swap. Thanks Andy!
Hi Ray,
Love your reviews – can’t believe this isn’t your ‘full-time’ job. I have sent alot of my tri buds to your site and they love it too!
I have narrowed down my Power choices to Stages and Power2Max. I thought it was a no brainer cost wise and performance for Stages since the new update, but in examining further, my bike’s stock components are not compatible with either. I have a 2009 Specialized S-Works Transition with S-Works Carbon crankset. The Stages Dura-Ace or any other Shimano or SRAM crank arms won’t fit on the S-Works crank nor will the Power2Max. I assume I can still keep my current 53/39 chainrings?
So I’m looking at a whole new crankset, which would bring me to Stages DuraAce for $1350 (+ Bottom Bracket I believe) or Power2Max Rotor 3D for $1283 (+BB likely).
The Transition is currently my only bike (I do Tris exclusively) so I am not likely to need swapping to a different bike at this point.
Looking at the quality of both products, what would you recommend?
Can I buy any of these through a link on your site, would love to give you a kickback for your work.
Wow, this is the first time I have read your blog, and I am super impressed. I can imagine how much work went into just this one blog alone – thank you. I have a question: I have a Garmin cadence and speed sensor that interacts with my Garmin 500. Given the Stages meter has a built-in cadence sensor, is there anything I need to do other than remove my cadence magnet from crank assuming I go with the Stages meter? I don’t believe the Garmin 500 can receive cadence data from multiple sources, correct (and I’m not sure how useful it would be)? Thank you again.
I added the stages but kept the Garmin speed/cadence sensor. I believe the Garmin gets cadence from the cadence sensor as it works to a lower RPM than stages claims. No issues either way.
Interested to know if a definitive answer was found on this question? I am running a Stages to my Garmin 500, and also connected to my Giant RideSense pickup which gives speed/cadence. All sources are detected by the Garmin, but I am not sure WHICH cadence is being recorded. I have my suspicion it is the Stages Cadence, as the numbers seem to be a lot lower than if I ride with the Stages disabled and cadence from the RideSense only. Anyone have knowledge or firm data on this? Thanks.
I reported the unusual power/cadence spikes to Stages and i promptly received a replacement the following day! Talk about speedy service. This may be due to the new firmware: Stages power meter is now able to capture power and cadence when the cadence is below 30 RPM. In fact, my Edge 800 was able to display power and cadence with cadence as low as 21 RPM.
Hey Ray, thanks for the great site. My question is this: which major power meter do you see as the most durable? I’m talking about actual physical durability. I’d like a PM for cyclocross applications, but with so much mud and rain and so many random crashes, I don’t want to go out there with an expensive component that’s easy to break. Stages appears to be a pretty good option based on it’s location on the bike, and I think Quarq might be pretty good too. Any comment?
I think in general all of the options are quite durable. There are certainly cases of breakage here and there that occur to folks across all units I’ve reviewed. Some due to manufacturer fault, and others less so. I just don’t see any trends though that place any given product in a bad place. What I do know is that Stages, Quarq, and CycleOps have incredible support from everything I’ve seen – and more importantly, everything I hear from readers that deal with support. Power2Max has ‘good’ support, but it’s a bit trickier in that their current manuf/distribution network makes it more complex to support issues as quickly as Quarq/Stages/CycleOps.
Colin the Quarq mtb crank does not last in rain and mub read above. I should receive my stages very soon so lets hope that is better.
The Stages website FAQ states: “What head units does my Stages Power meter work with?
The Stages Power meter will work with any ANT+™ enabled display unit, as well as Bluetooth 4.0 enabled devices, including Apple’s iPhone 4S.”
This gives the impression that I can buy the relatively inexpensive Stages crankarm and avoid the expense of buying a $200+ head unit by instead using the iPhone I already own as a head unit.
Is the iPhone a viable head unit to display watts during rides and analyze afterwards? If not, Stages should start building that app ASAP and I would be more inclined to get the crankarm.
Adam, for shorter rides, like less than 4 hours, it is viable to use apps on iPhone to display/record power data. For longer rides, the battery life of the phone comes into play. It’s difficult for me to use any GPS-related apps on my iPhone 5 for more than 4 hours without running out of battery.
If you have recent models of iPhones (at least an iPhone 4s) that come with Bluetooth Smart (or Bluetooth 4.0) support, the free Wahoo Fitness app will do what you want. It will display Power data (current power, average power over various time intervals) and it will save the ride data on your iPhone. When you are done with the ride, you can upload the ride data to a bunch of sports-related sites like Garmin Connect, Strava, MapMyRide, Runkeeper, TrainingPeaks and Ride with GPS. You can also choose to upload the ride data to Dropbox. I have personally tested the upload with Garmin Connect, Strava and Dropbox. It may be because i have iOS 7 beta on my iPhone, the ride information uploaded to Strava is completely wrong, showing elapsed time of 0 (it’s the same situation if i use the Strava app on my iPhone). I believe this is a problem with the Strava app and not Wahoo because the Wahoo app essentially uses the Strava app to upload the ride data to Strava.
The ride data is correct when seen on Garmin Connect.
Actually, a huge plus of the Stages power meter is that it uses ANT+ or Bluetooth to communicate to a variety of head units.
I use an iPhone as the “controller,” but it’s in my backpack (optionally mated to an external battery). I bought a RFLKT from Wahoo that displays the important ride data on a very small device that’s permanently mounted to my bike. I may go back to mounting the phone directly on the bike, but for now I like being stealthy. The new PROTKT bike mount will *sigh, eventually* have an external battery option — taking care of that pesky battery issue.
FWIW, I use the Wahoo Fitness app and then use that to upload to Strava, Trainingpeaks and Runkeeper.
The real killer is when mainstream Android gets all the profiles, etc., for low power Bluetooth. That’ll open up a flood of new devices that can be used as head units.
And slightly OT: I can 100% vouch for Stages the product as well as Stages the company. They really bend over backwards to provide excellent customer support, and I’m loving the meter!
I would buy a Stages power meter tomorrow. Only problem is, I CAN’T GET ONE. I am based in Australia and for some bizarre reason, they will not ship outside US/Canada.
I have been told it’s because they want to provide good aftersales support, but I don’t buy that. The cranks weigh only 20g – there would be no issues with shipping them back to the US if they need servicing.
I really think that Stages have missed a trick here with the slow international rollout. Interest in their product is currently at a peak. However, this is a VERY fast moving market. By the time they do begin shipping internationally, other power meters may have stolen their thunder….
It’s more of a customs/duty issue that’s the real challenge for international shipments. Australia doesn’t have import customs, but much of the world does. For example, in France, it would be a 19.6% tax each time something gets imported in. And even if you correctly declare the item, things gets messy and you still sometimes get taxed.
I’m pretty sure nobody wants to be more widespread than they do, but I’ve also seen companies struggle with getting the international side flowing correctly before customers onboard. Sorta a damned if you do, and damned if you don’t situation.
I’m based in Aus, and I got a Stages, and LOVE IT. was lucky though as I have a friend in the US that i got it shipped too, then he shipped it to me, total shipping $40 with insurance.
Thats the best bet, is Aus there is no tax on imports less that $1000 so as long as you list it for its real price and have a contact in the US to use, easy done.
There is also an option of using any package forwarding sites like shipito.com (there is large number of options – some are free, but have higher postage fees, some cost couple of dollars per delivery but have much cheaper shipping costs).
Any tips?
How loose is your on the crack? Mine seems to have a wobble? What’s your like?
matthew
Tips on?
My crank isn’t loose at all. If yours is, something is wrong. Definitely ring up Stages. I suspect it’s not actually a Stages issue, but perhaps something else going on. But they’re much smarter bike-component people than I (really, as long as my bike moves forward and doesn’t make too many noises I’m happy).
Enjoyed the review. I am curious why SRM was omitted from the test, given it is generally regarded as the “gold standard.” Regards.
Because I don’t have an SRM.
Every power meter has areas it does well, and does less than well. SRM is no exception to that rule.
Sorry I should have said that the stages sensor has a wobble on the crank arm. I have heard other people where the sensor has come off.
Would a little bit of elec tape/zip tie blur the watt figures?
Something’s wrong there then. Ring up Stages and have them swap it out. Everyone I’ve heard from has praised Stages support that they’re overnighting units for support issues. Ultimately, if it’s wobbling, then it’s got some sort of defect.
Superb review. I have nothing else to say.
From my understanding of material properties, it seems it will be much more difficult for stages to be applied to a carbon arm. They clearly are focusing on the metal cranks. Rotor cranks have that machined finish on the outside, but perhaps this causes issues for the connection of the strain gauges? Plus rotor came out with their own power meter, so maybe this is a conflict?
For SRAM Red/Force, the quarq strain gauges are all applied to a flat surface, metal at the spider. So this might be the Shimano Crank, non-SRM, alternative after quarq was purchased SRAM.
Has stages considered slapping another meter on the drive side arm as well? Still, the price would be less than quarq and clearly more accurate!
Thoughts DC?
Check out the original review, I talk about this a fair bit and what they are doing and their plans. Enjoy!
Incredible. This is as good as practically any PhD dissertation Ive seen in my field. Thanks for the effort!
I received my stages X9 Mtb crank about 2 weeks ago and have ridden nearly 400km all off road including some really rough rocky stuff. All I can say is Brilliant. Not a single spike or inconsistent data. I had a Quarq mtb crank previously and have compared data, I’m no rocket scientist but in my opinion the numbers are spot on. As far as durability goes only time will tell.
Stages approach to power meters is just so neat and simple just brilliant, I sincerely wish the best for them.
Thanks so much for yet another incredibly thorough review!
Great review. I heard from a friend/bike store owner that power meters are coming down in price. For someone like me, amateur, 50 yrs old, but still trains with power once a week on a Computrainer at a coaching gym, this seems ideal from a cost standpoint. Your review really cleared up a lot of questions for me (many of your reviews have done so!). Thanks!
Given your experience of power meters, after reading your informative garmin vector review today,…I was wondering the best way to get the most accurate results in terms of calibration pre, post, and during a ride if they apply.
Thanks!
It’s funny, I’m just putting the finishing touches on exactly such a post – for all power meter brands. I’m just about to send each model/brand chunk of text off to each company for complete validation (like I did with the Vector calibration piece).
My goal for that is to have that post out sometime next week. It’ll just depend on getting the information back really.
New stages power meter firmware, version 2.0.21. Not sure when it was released – Stages doesn’t seem to be announcing recent firmware updates on its site – but i installed it two days ago.
You mention, (but Stages doesn’t as far as I can see), that the power is simply doubled to calculate total power from left crank. Are you certain this is so?
My thinking is this:
1. Between two pedal revolutions you could assume the work needed is the same (i.e. no changes in air, road, transmission, or gravity resistance).
2. If the crank arm rotates with constant speed you could therefor assume the power inputted (by the legs) is twice the measured. But if the speed through the revolution varies, as would be expected if one leg pushes harder, and you can measure the crank speed (possible with the accelerometers) it should be possible to more correctly approximate total input.
Since both legs work all through the revolution as long as you’re clipped in, left/right dist would still be cumbersome, but I think the algorithm could be smarter than 2xleft power.
Yes, they are very clear that they are doubling it.
“P=2∗((Fave∗9.8∗L)∗(R∗.1047))
Reading into this equation: P is power (Watts). The (2) is a multiplier and our one assumption, which represents the doubling of our left leg power measurement. We feel this assumption is fair and we’ve tested it to be consistent. This assumption is also the key factor that allows us to produce the Stages Power meter to be more compact, lighter, more robust, and more economical than any of the competition.”
From: link to stagescycling.com
Yup, sorry, got stuck in an idea and lost my reading comprehension.
Poor chaps like myself are reluctant to purchase devices that equate to one of my paychecks. That said, I have held off on purchasing any new technology without a conclusive review from you.
I appreciate your reviews because of how thorough you are and how dedicated you are to finding information and providing it to the people. It takes a level of dedication that few have.
Thank you for taking the time from your 9-5 to inform the masses.
I have seen several posts that the Stages power meter is not compatible with carbon cranks? If you utilize the Stages left crank arm power meter with for example a SRAM Force carbon crank what would be the issue other than having one carbon crank arm and one anodized crank arm? Does this cause and issue in terms of measuring power and the algorithm Stage utilizes?
There’s no issues in mixing the two together like that. I confirmed this with the Stages folks.
Stages Power Meter only takes measurement from the left crank arm so it does not matter what you have on the right crank arm. I have the 2012 SRAM Red gruppo and the left crank arm on my bike is a SRAM RIval with the Stages power meter.
Ray, any idea if Stages has considered making their product also be an ANT+ to Bluetooth repeater? Might sell a few more units to folks who have Garmin HRMs and GSC-10’s but are logging with older 305’s and such and would rather just switch to an iPhone. I know RFLKT+ *might* be coming to do this, and there’s a HRM strap to do it, but if it were rolled in to something they were thinking of buying anyway…
This is assuming their hardware can do it, which seems likely, anyway.
I don’t believe they’ve ever considered it. But, I’d say that’d be a pretty darn cool idea – and something that would definitely help folks bridge over, especially those with ANT+ HR straps and the GSC-10’s for speed like you noted.
Given the technology pod is heavily powered by Wahoo, and Wahoo did this in the RFLKT, the path to enable something (though likely complex) may not be horrible. I’ll bring it up next time we chat.
Personally, that would also be an interesting ‘paid upgrade’ type scenario – for say $29 or something.
Hadn’t thought of it as a paid upgrade, but at that price point, I’d buy it. Especially if it’s a “with the hardware” upgrade such that if I sold the Stages later that upgrade stays with the hardware.
It really just hit me the other day…I’ve got Stages on a 4″ fatbike thanks to the fact that SRAM released fatbike cranks recently and the left arm is the same (prior to that, Stages wasn’t compatible with any of the existing fatbike cranks). I’ve also got a GSC-10 on it since I have always been an Edge 800/810 user (and thus generally use ANT+ HRMs), but the other day I was thinking it would be nice to just log with the phone I was going to have in my pocket for a short ride anyway. And on trail I really like the added accuracy gained by having the wheelspeed sensor figured into the equation rather than just GPS, since they all seem to short you some without it, and the delta can be quite high on really tight singletrack…
Any thoughts on Power Meter Protection offered by Stages? Worth it? Standard warranty is 1 year, but this adds crash protection and an extra year. $135…..do you feel this PM is fragile?
That’s tough. I don’t feel it’s fragile, and I feel that the customer support from Stages has been incredible thus far.
I feel that if it were $99, then it’d be an easier buy, but $135 for a $699 product seems a touch bit high after now having used it for a while and I feel pretty comfy with it.
Now I will point out that if you’re mounting biking – I’d probably consider it more than road/tri cycling. Simply due to rock issues, etc…
I mountain bike with it, I’m hard on equipment generally, and I didn’t think it was worth it. Maybe if it added 5 years at that price, but not just one, no.
I don’t know if they publish any prices, but I’d be shocked if their repair price was much more than that, honestly. Even on a very smashed sensor. I don’t care if it’s three times that, it’s just not worth it to me for one additional year.
Oh, but further to my point above, *if* I “needed” my Stages because it was the bridge between my HRM and speed/cadence sensor to my logging device (ie. if they did add ANT+ to BT bridging), I’d DEFINITELY be more likely to buy the extended warranty. So maybe that’s another consideration for adding bridging.
I did buy it. I agree, their customer support has been nothing short of fantastic. I’m a huge fan of the company. Getting another year of the white glove treatment seemed worthwhile. YMMV, but I generally get warranties for products that are at the beginning of their life (especially tricky products such as power meters). The additional year seemed about right — two years in, I’d be more likely to want to buy “the new thing” rather than fix the old.
And a power meter would be a terrible place for the ANT-to-BLE bridge. You really don’t want to change the battery on the power meter often (per the above, that’s the #1 opportunity to do something to mess up the meter). The bridge really needs to be powered on for the entire ride, including when you’re not pedaling.
I really think the RFLKT+ is a much better place for a bridge, presuming they make their funding target.
So there I was thinking it would be so cool if I could get rid of my Garmin 500 and go to a pure iphone 5 solution that is all bluetooth:
– wahoo RFLKT – check
-wahoo KICKR – check
-wahoo speed cadence sensor – check
-wahoo HR strap – check
– two stages powers meters – will not record cadence or power when your iphone is in your jersey pocket on either the wahoo app or the Strava app.. – bummer
back to Garmin and ant+
DC – can you please confirm/expand on the comment (#199) above? This setup of all Wahoo products (RFLKT, Speed/Cadence, HR) plus Stages is what I would be interested in but the comment above seems to indicate it won’t work? I currently use RFLKT + Wahoo Speed/Cadence and Wahoo HR strap with phone in back jersey pocket with no issues.