A bit over a year ago CycleOps announced their latest devices – and with it their first power meter that wasn’t in a rear wheel hub . CycleOps has a long history of power meter head units (and power meters), an area they’ve been at the forefront of for years. When the product was announced, many within the industry were skeptical on how accurate a power meter could be based purely on heart rate data. And further, for as low of a price as it was being offered (now down to $99). So, I’ve dug in to find out and separate fact from fiction from FUD.
Like all my reviews, they tend to be pretty in depth (perhaps overly so) – but that’s just my trademark DC Rainmaker way of doing things. Think of them more like reference guides than quick and easy summaries. I try and cover every conceivable thing you might do with the device and then poke at it a bit more. My goal is to leave no stone unturned – both the good and the bad.
While during the initial development period, I picked up a unit from CycleOps at Interbike that year (anyone could for free). I have since procured my own final unit, which is what this review is based on. If you find my review useful, you can use any of the Amazon or Clever Training links from this page to help support future reviews.
Lastly, 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. 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. Also, because the technology world constantly changes, I try and go back and update these reviews as new features and functionality are added – or if bugs are fixed.
Unboxing:
First up is the exterior box. Note that there are a few variants of the PowerCal unit floating out there. One includes just the PowerCal strap (combo heart rate and power). Another includes the strap + an ANT+ speed sensor. And the third includes a strap + speed sensor + calibration stick (ANT+ stick).
If you already have a Garmin Forerunner with an ANT+ stick, there’s no need to buy that stick package. They all work just fine with each other interchangeably. Same goes for the speed sensor. In fact, I see little reason to buy anything other than the $99 package (just the strap).
That said, this particular unboxing includes the extra pieces.
Cracking the box open, you’ll see the heart rate strap transmitter pod looking up at you.
After taking the top off the box, we’ve got the following little baggies full of goodness.
Those bags include the PowerCal strap (left), the speed sensor (upper middle), the slew of zip ties for the speed sensor (bottom middle), and the manual that you won’t read (right).
First up – the PowerCal strap and the speed sensor. Note that this isn’t a combo speed/cadence sensor, but rather just a speed-only sensor. Also note that not all ANT+ capable units support the speed-only sensor. Virtually every ANT+ unit out there supports the speed-cadence combo sensor, but less just the speed-only.
Here’s the manual. We can pretend you’ll read it.
Back to the speed sensor – you’ve got the transmitter unit, and the small spoke magnet sticking up there. You attach that to a spoke on your rear wheel, and the transmitter to your bike frame using the plethora of zip ties.
Here’s a bit better look at the heart rate strap itself. In many ways, it looks just like any other ANT+ heart rate strap out there.
Ok, with the unboxing complete, it’s time to dig into the details.
Detailed Breakdown of PowerCal functional areas:
I’ve taken a bit of a different approach this time with the review. Not substantially, but probably just enough to be noticeable to regular review readers here. Given the PowerCal is essentially just a heart rate strap that also spits out a power number, I wanted to focus on the different scenarios, edge cases and functional areas of the strap. I started off with section numbers in my review draft, but realized it actually made it kinda easy to walk through starting with the simple, and then getting to more complex scenarios. Think of it like a school lesson book upon each previous chapter.
1) Setup, Installation, and Pairing with other head units:
Setup of the PowerCal is amongst the simplest device you’ll have to setup out there. In fact, it’s not really any different than that of a heart rate strap.
And while it used to be that in the earlier pre-production PowerCals required that you calibrated them, that’s no longer the case. After a 3rd party (Colorado University at Boulder) conducted a study on the accuracy of the units they found that there were no accuracy advantages in most cases by calibrating the unit (done via mini-FTP test). The only thing it served to do was add more complexity and and more test workouts to users that otherwise might not ever wish to complete them. But I’ll dive into this more later on.
With us ready to start pairing, you’re going to be pairing it twice. Once for the heart rate strap, and then once for the power meter. Some head units (like the Joule GPS) support a ‘find everything nearby’ function – but that’s about the only one that does (a cool feature). Hence why most other units you’ll have to do the two-step tango.
First, we’ll take care of the power meter piece. This will vary based on your exact bike computer, but you’re ultimately looking for the section that allows you to setup bike profiles/details and then pair the ANT+ power meter:
Once that’s done, you’ll usually see a device ID of some sort, and a message saying either connected or paired.
In some models, you can even get additional information about the unit as well. Though not all bike computers have this.
Once your power meter is found, you’ll want to complete the same steps for the heart rate side as well. Usually the heart rate settings are found in one of two places. Either the person/user settings, or the bike sensor settings. It depends on the model. Ultimately though, you’re looking for something that says “Heart Rate Sensor” or “Heart Rate Strap”
Finally, a fun little note – if you attempt to calibrate the PowerCal using the automatic calibration button found in most bike computers, it will not succeed. The calibration button found there is designed for direct force power meters, and not for PowerCal.
The PowerCal calibration function is very different, and I talk about that much later in this post.
2) Looks like a normal power meter on units
The most important thing about the PowerCal is that it looks like a normal ANT+ power meter. As you saw in the previous section – it’ll pair like any other power meter does to any other power-meter capable head unit.
These include (not a complete list, just off the top of my head), the following units:
4iiii’s Heads Up Display
CycleOps Joule 2.0 & 3.0
CycleOps Joule GPS
Garmin Edge 500
Garmin Edge 705
Garmin Edge 800
Garmin Forerunner 310XT
Garmin Forerunner 910XT
Magellan Switch
Magellan Switch Up
Motorola Motoactv
Timex Global Trainer
Timex Cycle Trainer GPS
Various iPhone apps with Wahoo Fitness ANT+ adapter/case
Various Android apps with compatible phones (ANT+ chip on certain models, like Xperia Active)
With all of these units, comes the standard ANT+ power meter metrics that are typically available, these include the below – all of which work with the PowerCal:
Power (instant)
Power – Max
Power – Average
Additionally, any other data field offered on certain manufacture products that are dependent on the standard ANT+ data stream will work with the PowerCal, for example, these data fields:
Power (3-second)
Power (10-second)
Power (30-second)
Training Stress Score (TSS)
Intensity Factor (IF)
NP (Normalized Power)
Power Zones
% of FTP
Again, each of the above fields vary by head unit company – and not by the PowerCal itself. It’s merely transmitting the wattage that these different fields rely on. And of course, different companies can choose to implement the same fields slightly different ways – though most are fairly standardized.
2) Fluctuations in Power:
The single biggest difference you’ll notice between power numbers displayed by a PowerCal compared to most other power meters on the market is the fluctuation in instant power displayed on head units. In other words, the consistency (or lack thereof) of the power numbers.
Now, it should be noted that virtually all power meters display some sort of second to second variation that often concerns folks new to power meters. For example, a typical power meter will look like the below string (consider each number the following second). This is from a PowerTap hub across 13 seconds.:
114,117,117,118,104,130,116,120,108,106,106,119,108
Now, let’s take a look at some numbers from a PowerCal (these are aligned to the same 13 seconds as the PowerTap above)
35,68,130,163,225,258,260,230,200,105,75,0,0
What you see here is far greater variation between each second, as well as far more ‘super-high’ and ‘super-low’ numbers. For example, the 0’s and the 35/68.
Now, when looking at averages (and I just picked 13 random seconds), we see the following:
PowerCal: 135w
PowerTap: 114w
I won’t get into averages in this particular section, but you can see that while their methods are different, the overall averages are in the same ballpark (though, not the same base path).
To illustrate this a bit better, I’ve made the following video – which I’ve placed two power meter display units next to each other. The left unit (bigger Edge 800) is displaying power from the PowerTap, whereas the right unit (smaller Forerunner 910XT) is displaying power from the PowerCal. Both units are configured and setup identically, and both started at the same time.
Data displayed on Edge 800 (top to bottom): Instant Power, Power 3-second avg, Power 30-second avg, Lap Power
Data displayed on FR910XT: Instant Power (upper left), 3-second power (upper right), lap power (lower left), 30-second power (lower right).
What you’re looking at is how different the 3s (3-second) and 30s (30-second) power is between the two, and which one is most useful for pacing.
I’ve also placed the lap average on there as well, to allow you to get a sense for how the overall average of those units are comparing. Note that overall the units remain fairly stable, and fairly close.
3) Power Analysis After the fact – what the data looks like:
Before we get into some of the power files, I wanted to briefly cover what data looks like from the PowerCal, compared to regular direct force power meters.
At first glance, with some form of smoothing on – you may not notice much of a difference. It looks mostly like normal power meter data:
But as you remove the data smoothing you start to see just how jumpy the data is:
Compare a PowerCal and PowerTap on the same ride – and note how different the graphs look. Power meter data is always jumpy in general, but the degree that the PowerCal is jumpy is the interesting tidbit.
In the PowerCal (above), you’ll see that the data doesn’t hit the floor (bottom, zero-value) nearly as much as the PowerTap. This is because the PowerTap is instantly picking up when I stop applying force. So if I pause pedaling for just one second, it’ll capture that. Whereas the PowerCal takes a longer reaction time as it is based on heart rate.
This is even more visible when you look at raw numbers in something like Excel. Below, a few columns of numbers – one on a PowerCal, another a PowerTap, and a third, a Power2Max. Ignore the correlation between them (well, you can look if you want) – instead, note the line after line differences (going from top to bottom). The change is far more significant between each value on the PowerCal than the PowerTap.
We’ll get into what this means in a bit.
4) Short duration power accuracy (sprints/intervals)
One of the most common questions with the PowerCal is how it handles short intervals from a power measurement and responsiveness standpoint. The reason being that since PowerCal is based on heart rate data, heart rate data will lag slightly behind power output.
For example, if you’re just calmly riding along at an easy wattage, and then burst into a all out sprint – it may take 5-20 seconds for your heart rate to show the impact of that – meanwhile, your wattage on a direct force power meter (normal power meter) would have shown that immediately.
In the case of PowerCal, I did some tests comparing lap averages over different lap durations. I went out on a closed course and simply held sustained efforts for each length of time. These weren’t set to me holding any given specific wattage, rather, me just holding a heart rate value that seemed interesting. Effectively, these were intervals. Though, the exact heart rate zone isn’t terribly important. What’s important first is how accurate the PowerCal can be during shorter durations (because your intervals will vary just like mine).
Here’s the results (click to expand):
As you can see, the PowerCal seems to get relatively close down until about 30-40 seconds. At which point, the rate of change exceeds the PowerCal’s ability to measure the sprint. It did somewhat find on a 30-second attempt (#9), but had more problems in the 40-second one just after that. Above those times however, things were actually pretty close most of the time.
5) Full workout power accuracy (longer duration)
Now that we’ve covered the shorter sprint scenarios – how well does it hold up over the course of a workout?
Well, surprisingly well.
And that makes sense. At $99 the unit primarily targeted towards those interested in full-scope workout averages. Meaning, less focus on detailed lap by lap and interval analysis down to the watt.
In fact, this generally seems to align with most of the anecdotal data I’ve seen across many different cycling related forums. There are some outliers, yes, but most folks are pleasantly surprised at how well total averages perform. For fun, I pulled my four most recent rides:
Of course, total averages don’t tell the full story. And, many ardent power meter supports like to point out that total averages are useless – since they don’t show you important values like max efforts and what went into that. As noted earlier, you can arrive at a total average number many different ways. It’s how you arrived at that number that makes up a training session. Hence why other values besides averages are so important.
That said – for most individuals looking at buying the PowerCal, they are likely using simple speed today (MPH/KPH). Any cyclist will tell you that like other metrics – simple speed is just as dependent on wind, terrain, environmental factors like snow or rain, or even ones ability to navigate trail or road traffic.
Thus, in many ways the PowerCal isn’t much different here. But it does provide a overall wattage value to work with. Something that a simple speedometer doesn’t. Different folks will be able to interpret that differently. But most folks would be able to interpret a plotted graph over time showing improvements in average wattage/power over the course of a season. Hence why I still think there’s value here, assuming one understands the limitations (which you’re seeing I’m working through section by section).
6) TSS/NP/IF (Training Stress Score/Normalized Power/Intensity Factor)
These metrics are amongst the most commonly ones used when measuring the impact of ones training with cycling. Be it either in conjunction with your larger workout load (TSS/IF) or on a per-ride basis (NP). You can find lots more background information on these metrics here.
Both metrics at first glance level work just fine with the PowerCal with any power meter that support these Training Peaks metrics. Today that’s limited to the CycleOps units, as well as the Garmin Edge 500/Edge 800/Forerunner 910XT and the Magellan Switch Up.
However, deeper analysis shows that due to the high variability within the PowerCal data (as seen in fluctuations), you’ll likely get slightly skewed numbers. For example, the high spikes can lead to changes in these metrics – as it assumes you’re putting out brief extremely high level efforts (similar to a sprint). In real life, the act of repeated hard high wattage sprints with longer rest breaks is normally more impactful (training load-wise) than a low-intensity sustained effort. But the opposite is true as well, in that PowerCal often puts in many lower-value numbers that make it look like you’re riding easier than you are. Thus, when translated to emulated readings (that the fluctuations induce), you’ll see non-realistic metrics.
Taking a simple comparison I’ve taken a ride below that the PowerCal performed ‘rather well’ on. Meaning, that its overall wattage was quite similar to that of a PowerTap on the bike at the same time (3 watts). Running these metrics, you can see the differences below:
Both of these metrics were calculated online using TrainingPeaks in the same account – to eliminate any head unit discrepancies with setup of TSS/NP/IF on the unit itself (both recorded all zeros and at one-second intervals – which is how I record all test data).
You’ll notice slight discrepancies in other metrics as recorded by the different units, though non affecting TSS/NP/IF.
6) Indoors Riding (Trainers)
I tend to do about 80% of my workouts indoors on a trainer. Both because you generally get higher quality workouts on a trainer (it’s relentless), and because it’s sometimes just easier living in a city (you get more bang for your training buck).
In doing so, it’s interesting looking at some of the numbers related to the PowerCal. These workouts were part of larger trainer accuracy tests I was doing, so it made it simple to grab the numbers for the PowerCal.
You’ll see some of the first portion of the structure within the workout I was doing, though I didn’t detail it all out as much of it was repetition. Ultimately though, the numbers speak for themselves.
Note that as is the case in all of my power meter accuracy tests – the power meters are calibrated (where applicable) at the 10-minute marker, just after the warm-up watts. The labels on the left-side correspond to chunks of the workout. For example ‘Warm-up Watts’ is a 10 minute section, ‘Calibrate Watts’ is a 2 minute section where I don’t stop anything recording, but do complete calibration.
Trainer Workout #1:
Trainer Workout #2:
This was part of a interval workout of sorts I did. Again, you see that the overall numbers are fairly close. Each interval was 60 seconds long, and each rest the same. You’ll notice that the PowerCal overestimates the rest interval by quite a bit – likely because my heart rate was rather high. Whereas the other power meter instantly recognized the lack of wattage. All my rest intervals though are still pedaling. There aren’t any stoppage points here.
I picked a few random intervals to show in the table below (as opposed to painstakingly doing the Excel math for all of them). The intervals were not at a set wattage per a CompuTrainer (or similar), but rather in a rough range, hence why they vary interval to interval.
Overall, I see week after week pretty impressive results when it comes to trainer accuracy of the PowerCal. It is interesting in the above workout to see what appears to be some drift in the older version of the Power2Max.
7) Coasting/Descents and the results
Perhaps one of the more fascinating things to look at is how PowerCal handles descents – or coasting in particular. Obviously you can still descend and put out a lot of power (as I painfully learned while riding with some pros in Colorado last year).
But in general, if you’re coasting, you aren’t likely putting out much power. Often called ‘soft-pedaling’, you may be just putting out a few dozen watts, simply enough to turn the crank around slowly.
I took the below snippet from a recent ride as I descended down a hill. Let me walk you through what you’re seeing on the charts.
Brown: This is the hill, or the descending of altitude. From left to right, you see that I’m largely going downhill.
Teal Line (light blue): This line is my cadence. You’ll see it’s dropping often down to 0 (the bottom). But generally being fairly light I’m just pedaling around 70 or so RPM – not pushing it at my usual 90-100rpm.
Blue Line: This is my heart rate. The scope of the graph makes it appear as though it’s a constant – but in reality, at least for the first portion, it goes down.
Red: Power. Simple enough, this is the PowerCal’s power output.
Now, with that background, flip to after the picture and I’ll explain what’s going on.
First look at the left third of the chart, and in particular, the bottom portion where the red power and cadence are displayed. Note how there’s a slight delay between when I pedal (and the value jumps from zero), to when the power is registered?
You can see it pretty clearly above – teal always leads the red. Like cat and mouse.
Now, if you look up at the heart rate, you’ll see tiny little jumps each time I start pedaling. This is logical, since for every action there’s some sort of reaction. In my case the energy exerted pedaling requires some level of heart rate (effort). Each yellow highlighted section shows the increase in heart rate, causing the increase in power displayed.
Of course, cadence as a metric isn’t taken to account by PowerCal. Rather, I’m just using it as it’s a very easy metric to show what my pedals are actually doing above.
Now the important thing here is that it’s about rate of change – not about straight heart rate. Note that as I come down in heart rate (blue) and start to flatten out, the unit realizes I must be applying more wattage. Otherwise, my heart rate have continued to decline. Then notice that as the rate of change decreases (heart rate), it means I’m applying less force – and thus less power. And therefor you see the red start to taper out.
Of course, if you look at the teal line, you see this confirmed within cadence. Now, I could have simply changed gears and lowered by cadence but increased my power. But that’s not what happened.
In fact, below, taken from a PowerTap – shows a fairly similar power curve:
Finally, looking at stopping (when my bike stops rolling, generally not due to a crash). In the below graph, I stopped. For what I assume was a stoplight/stop sign, though it’s not clear. What is clear is that my speed went to zero for about 15 or so seconds.
Speed is shown in green. Whereas power is shown in red. You see that as you’d expect, power zeros out before speed (you stop pedaling), and then speed flat-lines. It won’t always be quite as clean and with complete zeros as this (note the tiny little red bump up in the middle of the first stop) – but it gives you a good idea of what it looks like.
In summary, it’s not actually at all about coasting or descending – rather, it’s actually just about heart rate. More specifically, change in heart rate, and that rate of change.
8) Calibration – You can still do it.
The PowerCal calibration option was effectively removed as a requirement this past summer upon release of PowerCal. Initial pre-release information and units required/preferred a calibration test occur not only prior to use, but also every “4-8 weeks, as fitness levels change”.
However, upon release this summer, CycleOps removed the calibration requirement, noting the following (in an e-mail to the Wattage group):
“PowerCal can be calibrated but based on the study conducted at CU-Boulder there wasn’t any indication it addressed any of the expected short falls relative to accuracy so it’s not really worth the effort. Keep in mind this is terms of a sweeping recommendation across a wide population of athletes, there were instances of the calibration significantly improving accuracy across all activity types for some users. We just couldn’t find a correlation between anything specific for those that the calibration worked for and those that it did not.” – Jesse B. – CycleOps.
As noted, PowerCal can still be calibrated, but in my testing I haven’t seen any substantial differences between the initial test unit that I calibrated the first time around, versus the new unit that I have that doesn’t require calibration.
For those interested in calibration however, the test is essentially a threshold test of sorts, and the official documented procedure as as follows. However, it does require the use of a normal power meter (direct force power meter), such as a PowerTap, SRM, Quarq Cinqo, Power2Max, etc… Ultimately, you’d want to ensure that power meter is correctly calibrated.
In fact, here’s the full list of things you’ll need:
1) Power meter (direct force)
2) Heart rate strap
3) Head unit (bike computer that can record the HR and power data)
4) ANT+ USB stick (found with various Garmin devices, some PowerCal packages, or solo)
Then, you’ll go ahead and pair that power meter to a head unit (bike computer) of your choice, along with a heart rate strap. You’ll want to ensure that can be imported into the CycleOps PowerAgent software (downloadable on their site, used for analyzing workouts from CycleOps devices).
Once all that’s set, perform the following test:
Calibration Test Protocol
5 min warm up
3 min Very Easy
3 min Easy
3 min Moderate
3 min Moderately Hard
3 min Very Hard
In their initial documentation, they included the below graph as a general indicator of what you’re looking for consistency wise:
Once you’ve got the data imported into PowerAgent, you’ll want to go ahead and open the workout up in PowerAgent.
Highlight the section of the ride beginning with the warm up to the end of the fifth stage. Go to Tools > Configure PowerCal. There will be a pop-up window with the calibration highlighted. Click OK. Another pop-up window will appear confirming the new parameters. Click OK. A second pop-up window will appear asking if you would like to update the PowerCal. Make sure the ANT+ USB stick is in (you’ll need one by the way) and click OK. When finished it will confirm success.
When finished and ready to workout pair the PowerCal as a Power and HR sensor and you’re ready to go.
9) Running (why not?)
Last but not least…
Like Mythbusters, I like to take this beyond the intended myth. And this is one of those cases. Many folks have pondered how PowerCal handles running – and whether there could be any value pulled from it. Of course, today there isn’t a direct equivalent to ‘wattage’ for runners. There’s no ability to correlate an effort on a hill with that on the flats. One could have two equal wattage efforts and that would clearly be seen on a bike – but far less so with running and pace.
Ultimately, PowerCal will happily provide you with wattage data for your run. In fact, PowerCal will happily provide you with wattage data anytime your heart rate is pumping. Be it running, yoga, fencing or simply having sex. If you got blood flowing, PowerCal’s there to capture it.
But correlating that data to something useful is where it becomes challenging. For example, on a treadmill workout today, beyond the first two minutes, the treadmill was set on a specific inline and speed. It never waivered. In the real world – that would mean that my output was the same. But in the PowerCal world, it instead wavered based on heart rate – which slowly climbed (mostly due to lack of cooling).
Personally, I’ve found metrics like Training Peaks Graded Pace far more valuable for measuring run to run performance across differing terrain on different days.
Now, make no mistake – wattage or an equivalent will absolutely come to running. Not this year, likely not next, but it’s out there – and there’s a number of different teams and companies working on it. Of course, just like cycling in the early wattage days, it’s going to first look like a jumble of numbers and then take years to get to the point of really being able to make the most of the data.
It’ll come though, someday.
Summary:
At this point I suspect you probably have a pretty good idea of whether or not the PowerCal is a good tool for your training needs. But, before I give you some parting thoughts, here’s a quick table of pros and cons.
Pros and Cons:
Pros:
- Cheap, really cheap
- A gateway drug to full blown power meters
- Compatible with any ANT+ power meter device, easily integrates with existing devices
- Includes ANT+ heart rate strap functionality as well (you can use that part standalone for a run, which I do all the time).
- Can be calibrated, if you want to venture down that path
Cons:
- Shorter duration accuracy is rough
- Longer duration accuracy depends on many variables
- Pace fluctuates quite a bit
- May not be as accurate for everyone, highly individualized
- Calibration procedure requires repeated testing, may not improve accuracy
Final thoughts:
PowerCal isn’t marketed as a 100% accurate power meter. Nor as a tool for elite athletes (or any advanced athlete) to use as a hard core pacing device in a race or even day to day training. Instead, what it does offer is a low-cost method of getting a rough order of magnitude of your power level on a given ride. CycleOps is rather straightforward about this, from their own site:
“The PowerCal is not as accurate as a PowerTap and not intended to replace one. Research has shown varying degrees of accuracy based on individuals and types of riding. Accuracy will depend greatly on the individual and type of riding.”
Now there are many alternatives that can estimate power information after the fact – some of them free or relatively cheap. However, most of them are just that – after the fact, and separate. If you want some sort of integrated metrics that automatically show up in whatever bike computer you’re using – there’s really only two choices: PowerCal, or a normal power meter.
Note that you shouldn’t take a PowerCal wattage number and attempt to compare it against someone else’s power meter number. There are just too many variables. It’s better for plotting progress against yourself over time.
In my mind, the perfect target audience for something like PowerCal is actually my Dad. He normally rides about 100 to 150 miles a week, but he doesn’t race (triathlon or cycling). Rather, he rides to enjoy riding and to stay fit. Today, he uses simple speed on known courses/routes to determine his improvement week over week. While there are pitfalls to this, that’s the only tool in his (and most cyclists) bag to work with. Something like the PowerCal would give him a general idea of his improvement within the season. It wouldn’t be perfect, but it would work – as seen by not only the vast majority of the data here in this review, but also many other reviews and data points out there.
But as noted, it’s not for everyone. Personally, I wouldn’t use it day to day in my training, because my training is focused and specific enough that I need to ensure my numbers are consistent and accurate from session to session and within a session at shorter intervals than the PowerCal can respond to. Though, I would point out that I do believe the vast majority of power meter users today don’t get truly accurate and consistent numbers session to session. Instead, they look at trends. Merely looking at some of the differences you can see above between the PowerTap and the Power2Max in my data is a obvious indication of that.
Ultimately, the PowerCal is just a tool. As I always note in power meter related reviews, you still have to go out there and do the hard work to get better. This is simply one more (low-cost) tool in your bag to try and capture, analyze and make improvements on your work. Good luck!
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Ray, for the trainer intervals, what power meter were you using for pacing your intervals? After some intervals there is a big discrepancy between the Power2Max and Powertap. Are you using the new P2Max with that temperature compensation update?
Hi Ray,
I am a huge fan and supporter of your blog and did end up making a purchase through clever training in support of you. However, I have never had such poor customer service ever in all my experience of shopping online and am hugely disappointed in my experience.
I’ve left countless voicemails and emails with them, only to have them be unanswered. I hope you can understand my frustration.
From now on, I will only be supporting you via your amazon link.
Looking forward to your upcoming posts.
Hi Rafael- This is with the older Powr2Max. However, the only difference I saw was that one that I noted above. Interestingly, indoors.
Hi Joey-
I’m super bummed to hear that. Can you shoot me a note with your order number. I’d love to follow up and ensure it never happens again. But I do want to thank you for your support.
I don’t get to see pictures at work, so I’ll have to read through this again later, but my main concern is in regards to your last paragraph where you write about who you feel the powercal is intended for.
If it shows power based off HR, it is basically using an average power value for a given HR (I’m sure it’s very complicated though and probably has to do with how fast your HR increase among other variables). Right? So, if you improve over the course of the season to where (form a powertap) you power increases 20 watts at the same HR, how would the powercal see this?
The powercal to me just sounds like they took the idea of matching a power curve from a trainer to speed numbers, but applied to to a power curve based off of HR. Can you comment on this?
A power meter’s appeal is accuracy. Not too much of that is offered by Powercal, but that is reflected in the package. Power2max cant be afforded the same margin of error. A comparison of accuracy and precision would be appreciated.
Husain
@hu3ain
So. I have a few questions.
1. I didn’t see anywhere that you entered your body weight. in terms of actual wattage that would appear to me to be an essential calibration metric.
2. If all we are interested in is the final whole of ride average then why not just put it into the post ride analysis software. Do you know what the patent coverage is like? can you advise if there are any patent markings on the box/documentation?
3. You note that it doesn’t make use of speed or cadence. this is strange as it would appear to me to be a very sensible thing to do. it would certainly help solve the coasting problem and I suspect could be used to derive more accurate power models as well. Given that it’s likely to have upgradeable firmware I wonder (again subject to patent exclusion) what could be done on the 4iii’s Viiiva to do something similar.
4. If I can find a cheap one somewhere I might give it a whirl on the Concept2 Erg and see how the numbers correlate.
I’m curious to know how this would work for those of us on certain heart medications, such as beta-blockers, which artificially lower our heart rates. I’m guessing since it relies heavily on heart rate data that the numbers would be very inaccurate. Does the manual say anything about this possibility, or do they simply assume that people with conditions simply aren’t advanced enough to want power meter tech?
you missed an important ‘Con’. How would you ever be able to tell if you are getting fitter?
Similar question to Chris’s: how does it show power improvement over a season? If it’s based on HR, wouldn’t it only show a power increase over a season if there was an increase in average HR over the season? And in fact, HR at a constant speed should drop over a season. It seems that it would need to incorporate speed in its calculations to show power increase over a season.
One way that it might add something over normal post-ride analysis would be if the module internally measured R-R inter-beat timings, and factored that into the power calculation.
That’s something that’s missing with normal ANT+ HR, and where Suunto can score with their own straps (although that will presumably be lost e.g. on the Ambit if you use an ANT+ HR when that firmware update hits).
So, do we know if the Powercal can do this?
If not, it seems its only real advantage is in real-time data, as Ray says.
7Ray,
I know you’re a fan of SportTracks. I’ve been using the GPS2Power plug in, which uses weather and Garmin data to estimate power. You can look at a graph of power over time as well as average power for the ride.
Obviously the ST plugin is only after the fact analysis, but given your comments about your dad (who sounds a lot like me:)) using the PowerCal to look at improvement over time to time I’m wondering if you could comment more on the relative application and value of the ST plugin and the CycleOps device? Thanks!
Ray – it’s weird that the P2max would drift that much considering the indoor ride shouldn’t have that much temperature difference. P2Maax was on my considerations to rplace the powertap, but that scared me.
cdmackay the Forerunner 610 and 910xt can record r-r data to be analyzed with Firstbeat athlete, with the regular ant+ hr strap.
Is powercal compatible with the soft strap of Garmin Premium Heart Rate Monitor?, i think will be more confortable than the powercal. Thanks.
Hi Chris-
RE: Mapping of HR to HR values
Sorta, but not quite. There isn’t a 1:1 mapping, meaning my 140bpm isn’t the same as your 140bpm, thus, you can’t explicitly map it to say – 200w – for both of us.
Beyond that, much of what they are doing is pretty much trade-secret, which is somewhat logical they don’t want to say – as that’s basically all there is to the product (the sauce).
Hi Anon/hu3ain-
RE: Power2Max
Correct, I have a new Power2Max unit that’s getting installed on there, but it wasn’t on there then. The only one you saw the variation was during inside interval interestingly. Many of the others I actually re-calibrate a few times along, knowing the temp change shifting limitations of the Power2Max.
Hi Chris-
RE: Body Weight
No, body weight needed/utilized. Wattage has no bearing on body weight, only w/kg (which is head unit driven). Body weight is also used for calories.
RE: Why not just average software post-ride
As noted above, it would still allow you to do longer-interval wattage sets (roughly about 30-40 seconds) and get half-way decent data.
Additionally, it then ties you to a given software suite (i.e. Sport Tracks, etc…).
RE: Patents
The box photos I have handy (I’m travelling) don’t show one, but I do know there are patents either pending, or approved, from previous conversations with them.
RE: Speed/Cadence
Originally, very early on in the prototypes there was logic in the Joule unit to make use of speed sensor with it. Though, that wasn’t carried over to other units.
Ultimately, there’s likely the ability for it to talk directly to another ANT+ sensor (depending on the chip in there), thus potentially allowing you to pre-pair it with a given speed sensor.
Hi Anon-
RE: Heart medications
In general, I think you’re good on data as long as the medication doesn’t affect the rate change. Meaning, as we age, our max HR values slowly decline (i.e. a younger person could relatively easily hit 190bpm, but an older one not as much).
Hi Morey/DS-
RE: Being able to tell if you’re getting fit
Power alone doesn’t tell if one is getting fit. It’s always two variables. Power + X. Power + Heart Rate, Power + Time, etc… I can easily simply increase my power over the course of the season, but that wouldn’t show I’m getting fit. What would show that is a set/constant power + a decrease in heart rate (average). Or, a known TT course (no wind) + a decrease in time and an increase in power. It’s no different than any other PM out there in that respect.
For me personally, I use HR + PWR on a trainer. At a given HR level, I know my wattages, and I aim to improve those (generally I do that).
Hi CD-
RE: R-R
R-R isn’t actually a function of ANT+ HR, but rather, a function of the head unit recording the data. Companies pay FirstBeat to utilize the technology on a per product basis (i.e. FR610, FR910XT, etc…). Rafael also later on noted this (albeit after your comment) as well.
Hi Anon-
RE: GPS2Power
Indeed, he could use that as well. Doesn’t solve the trainer piece, or being tied to a given application – but it’s definitely something he could use.
Hi Rafael-
RE: P2Max
Indeed, I’m looking forward to getting the new unit on there.
Hi Xorga-
RE: Premium HR Strap compatibility
Yes, no problems in swapping to the absolute latest strap. For those curious, it’s also compatible with the Polar HR strap (not the Polar pod or watches, just the Wearlink strap).
Thanks all!
Thanks for the detailed review.
I’m unclear on how it adjusts its power estimates for riders of vastly different fitness levels.
Regarding this comment:
“Hi Morey/DS-
RE: Being able to tell if you’re getting fit
Power alone doesn’t tell if one is getting fit. It’s always two variables. Power + X. Power + Heart Rate, Power + Time, etc… I can easily simply increase my power over the course of the season, but that wouldn’t show I’m getting fit. What would show that is a set/constant power + a decrease in heart rate (average). Or, a known TT course (no wind) + a decrease in time and an increase in power. It’s no different than any other PM out there in that respect.
For me personally, I use HR + PWR on a trainer. At a given HR level, I know my wattages, and I aim to improve those (generally I do that).”
The only measure of fitness that matters is whether your power and/or W/kg for durations of interest/relevant for your goal events has improved.
It matters not what your HR does. If you can’t put out more power, you are no fitter.
I’m not seeing how this device can determine changes in actual power output.
And a P2M < Powertap readings tells us at least one of them is wrong. Do you know which?
(I do sell some DFPMs but like to stay well informed on what’s out there).
Hey Ray,
Cool review, really considering buying this device, cause it is a cheap start to power meters.
But I have only one question. I understand that the powermeter is vary sensible for heart rate changes and couples this to increase/decrease of power.
But how can the strap “see” the difference between my father (80kg, pushing 100 Watts at 170 bpm) or a Tour de France rider (80kg, pushing 300 Watts at 170 bpm)?
As far as I understand they will result in the same power output…
Hello Ray
Nice Blog you have I allways enjoy reading the reviews.
How do the results of the PowerCal relate/differ to the powerresults shown in Strava.
Beside the fact that you can see your results while riding of course and in Strava it is shown after.
Grtz
Wimm (Netherlands)
Hi-
Values of NP and VI are too far off for the Powercal to be used as a pacing device. The PW:HR ratios in both screens are typical of a perfectly paced event and a bad strategy (-7.06%).
Power measurement for runners would be awesome. Wished that the normalized graded pace metric would feature in 910xt.
Amazing review DCR
@hu3ain
Hi Alex (and Tom)-
RE: Adjusting for different riders
This is the part that pretty clearly falls (unfortunately) into the patented part. I’ll try and see if I can get a bit more clarification on it. I’ve asked a few times in person, but haven’t got any clarity. In looks at many other data points by different riders posted out there (with very different power profiles), it does seem to have enough logic built into it that it works (for most, albeit not all). I will note that Jesse from CycleOps did make this comment back on ST a while ago:
“This was our initial concern as well and why we assumed a calibration would be needed. However, in testing that assumption in the lab it was pretty clear the calibration did not provide a significant improvement across our intended customer base.
We concede the product won’t work for Lance [Armstrong]. We’ve set it up for a reasonably fit athlete knowing that the established issues with using heart rate to determine energy expenditure are bigger limiters for PowerCal than the absolute power to heart rate relationship of a given individual relative to another.”
RE: W/KG as a measure of fitness
You noted “The only measure of fitness that matters is whether your power and/or W/kg for durations of interest/relevant for your goal events has improved.
It matters not what your HR does. If you can’t put out more power, you are no fitter.”
Actually, W/KG isn’t a measure if fitness change. It’s merely a stated value. Ultimately, I can change my watts/kilogram by simply putting out more power. That doesn’t mean I got any fitter. It just means on day 1 I did an easy ride, and day 31 I did a harder ride.
You always have to combine power output with some other metric to meausure improvement. Time, distance, HR, something. Unless you’re talking a straight FTP test, but even that has defined parameters. That’s true of any power meter.
RE: P2M < PowerTap
Yes, as noted above, in that case where the P2M was showing odd numbers (I put it below the chart as well), it’s pretty clear the P2M was having drift issues (common for the older units) – something I can easily see in the chart. Outside I’m pretty good about doing a number of calibration checks every 15 or so minutes. Though that time indoors I’m surprised to see such a variation. Again, for that particular one, the PowerTap data alongside makes it fairly clear what’s going on.
Hi Anon-
RE: Strava comparison
Hmm, I’ll upload a few of those rides to Strava a bit later on tonight and see how the numbers mesh. Fun idea.
Hi Anon-
RE: NP/VI
Definitely agree. However do note that those two screenshots showing PW:HR ratios weren’t a race, or anything paced. It was merely a ride with plenty of city traffic involved on both front and back ends.
Thanks all!
Hi Ray,
great review, as usualy. I got excited, that I would finaly get wattage data for my running. I purchased the unit from Clever Training already. I was well aware of limitations of the PowerCal (thanks to your review), but I was unaware of limitations of my FR910XT. In Run profile the watch does NOT show Power values! Does it mean, that if I want to use PowerCal while running, I must set watches to Cycling profile? Or is there other way around?
Any advice appreciated!
Regards
Dalibor
Meer Nederlanders die er eentje willen bestellen? Dan kunnen we een groep-aankoop doen?
(Any people from Holland wanting to order one? Maybe we can split the order costs by Clever Training.)
Ray – Excellent review, as ever. I do short time trials and the Powertap (that I rent) is good for ensuring that I don’t go off too fast at the start, when heart rate takes 3 or 4 minutes to level off. Do you think the algorithm would help pace the early stages of a time trial properly and be useful for (15k and 40k) time trials generally?
Thanks!
Richard
Ray,
Since heart rate is the only thing being measured, shouldn’t power wattage be available from any heart rate device as a post processing function? I know “Ride with GPS” does some sort of power calculation in any activity that captures heart rate. During this after workout processing, the lags could be determined and factored out of the calculations.
Ray- you’re right about power, but you’re getting lost in the semantics. Unless there’s something I’m missing- There’s still an important CON to this device. Let’s say last year I was able put out 200w for 20min at a HR of 150. this year I’m able to put out 230w for 20min at a HR of 150. How would the device know? Lack of measurable improvement is a lack of an important motivational as well as practical item.
I was told I needed to buy the Powercal with the speed/cadence sensor if I didnt already own a ant+ speed/cadence sensor. Can you confirm that the powercal doesnt use either speed or cadence to calculate power and therefore I don’t need to clutter my bike with the sensor
Hey, I read your post from last year about riding with the pros…would you consider putting out a “DCRainmaker” cycling kit? I’m sure there are enough people that read your stuff that would pony up for a kit. Think on it.
I think one way how to know the difference in the case “Let’s say last year I was able put out 200w for 20min at a HR of 150. this year I’m able to put out 230w for 20min at a HR of 150″ is the factor of how fast does HR change towards the 150 bpm in these 2 scenarios. It seems the unit measures wattage using HR changes, not absolute value. An untrained person’s HR increase pattern should be different.
Xorga and Ray,
I purchased the PowerCal a couple months ago and thought the same thing about the latest strap being more comfortable. The powercal did not work with the latest garmin premium strap with the hook attachment. Were you able to get it to work Ray?
Anyways, I ended up returning the strap. It was more for post workout analysis and was rather useless during rides which I was more interested in.
Hi ray,
I can see this is an affordable way to get power data India garmin device, but couldn’t this all be emulated with an alogorithm within a smartphone app, or ultimately garmin firmware? There is no need for the info to be churned out of the HR strap itself?
I can still see a market for this though for people with existing sports watches etc.
David
Hi Dalibor-
RE: Run watch
Correct, the running profile on the FR910XT does not allow connect to a power meter. Thus, you have to use the cycling profile. That’s what I did above (about to add in an example showing data while running here in a little bit). About the only unit that you can create a ‘custom’ blend on is the Magellan Switch/Switch Up – which would allow you to pair to the power meter, but have all the metrics shown in ‘runner-friendly’ pace.
Hi Tom-
RE: Holland Group Buy
If you find more interest let me know, also, I can also add it to the Week in Review.
Hi Anon & a few others
RE: Post-processing options
Yes, absolutely – there are definitely other options out there, with varying levels of input and success for each. Ultimately though, the appeal of this product over those is the lack of requirement for post-processing. Of course, different strokes for different folks.
Hi Morey-
RE: CON
Now I understand what you’re getting at – which is that your concerned over time if your fitness improves, your power will effectively ‘drift’. I’m not seeing that as the case. I used a unit last fall when my fitness was notably higher, and then compared it to this fall/summer, where my cycling-specific fitness was lower. I’m seeing them track pretty closely. Ultimately, that’s why the product ‘works’ across people of differing fitness profiles without calibration. Otherwise the product would just work for me – Ray – and nobody else.
And remember, there is no direct mapping between a given BPM value, and a given power wattage. That all comes with their patented algorithm piece, which I can understand why they are hesitant about sharing.
Hi Tosin-
RE: DCR Kit
It’s something I’ve looked into, but first need to find a kick-ass graphics person to make something that’s both classy and awesome. Someday!
Hi Victor-
RE: Straps
They definitely should be compatible. I know I’ve swapped it back and forth without issue at some point over the last few months. Let me double-check again on that one when I get back from this trip, but I’ve been mixing and matching virtually all of them for a different review without any issues.
Hi David-
RE: Emulation in-phone app
Yup, absolutely as above. I’m sure there’s a few apps out there I don’t know of (I know of ones doing it post-ride and on computer/site). But ultimately, I’m sure we’ll see more – both apps and refinement of the algorithm from others.
Thanks all!
Interesting. I wonder how the HR to Power relationship works. In cycleops’ defense- I have noticed for myself- that as my FTP has gotten better- one of the things that changed was that I am able to sustain a higher HR for a longer period of time. This may be the opposite of running, where as I progressed, I was am able to run a faster pace at the same HR.
These relationships generally aren’t discovered in a vacuum by companies like Cycleops. For instance- for the Nike+ they used 40 year old research that defined the inverse relationship between foot ground time and speed, which is surprisingly consistent person to person, allowing them to develop a very inexpensive foot pod. So- perhaps there’s a research paper out there that forms the basis for the HR to Power model they capitalize upon. Might have to do with HR rate of change- both up and down, that gives a metric of fitness level and then the power output is extrapolated based on this factor? Maybe they hired Coggin as a secret consultant?
I’ve had a PowerCal for almost 2 months now. Your review pretty much hit the nail on the head.
For post-ride analysis I find that hrTSS is more ‘real’ than the PowerCal TSS. However using the PowerCal for intervals of 5min plus (with TrainerRoad) gives a very similar output to TrainerRoad (for TSS and IF).
In addition, the PowerCal is of great use when on travelling, and having to use a gym or spin bike, once you know what your FTP is on the PowerCal.
What do you think the advantages are of getting the PowerCal calibrated; have you carried out any testing with a calibrated PowerCal?
Ultimately, the PowerCal has peaked an interest for me that will lead to the purchase of a DFPM.
Great review, as always. Love the depth.
I was looking for a inexpensive powermeter for my mt. bike and cross bike in the winter/summer. Its not clear if anything is involved in switching between bikes since it is using HR primarily if I was using the same Garmin Edge 500 with those bikes already in and each device already has a ANT+ speed sensor.
I have to admit that I don’t see the main advertised use being useful at all. If HR is good enough to measure and track power, then why not just use HR, pace off of power etc etc.
But one thing I DO see it as useful for is for data junkies at spin class or on an exercycle.
You can bring this with you to class and get an idea of your TSS and so forth if you feel like you need power data from every workout.
Hi Ray,
Long time lurker, first time commenter.
Regarding your comment about using this for running. I think there is more utility than you are giving it credit for; it actually makes sense that on the treadmill your power output climbed, and not just because the heat in the room caused your heart rate to increase. Running is unlike biking in that the machinery translating power from your muscles is not as consistent – form breaks down over time/distance, which should increase how much work you are doing. I’ve often thought about this while monitoring my heart rate on long runs. By the end it feels like it takes much more work to sustain a given pace, above and beyond the increase in heart rate. When I am tired and my heart rate is up, much more effort (from my perception) is needed to increase pace or go up hills than at the beginning of a run or when my heart rate is lower. I think the power estimate from PowerCal could be used as another variable to track in addition to heart rate to get a better estimate of improvements in running economy. I’m not sure you would really be able to disentangle improvements in running efficiency from fitness, but this might help.
Random question – did you have any issues with static from wearing synthetic material shirts affect the output from PowerCal? I get that with my Garmin heart rate monitor in the beginning of some runs.
I’m curious about the accuracy on low RPM high torque intervals? Since your heart rate stays a lot lower and the sensor isn’t reading cadence are the power readings going to be accurate?
Hi everybody,
Has someone a comparison to the calcated power from Strava?
Its just another algorythm but powercal seems to be closer to reality
Ray, good stuff. So if I understand it correctly, Powercal is fairly consistent for intervals above 2-3 minutes?
And how does the Powercal work for total energy output? I’m thinking that the Garmin gives me total calories for a ride; do you get a Kj total from Powercal that can be used when looking at losing weight and knowing energy expended?
I’m genuinely sorry to read that you do 80% of your workouts indoors on a trainer.
Riding a bike is one of the greatest thrills that I know.
80% of workouts on a trainer almost always gives a more predictable training outcome than being out on the road. As well as a likely necessity for someone that travels a lot, it’s a very good way to get very serious bang out of every time you get on the bike.
@dave, if the only reason you ride a bike is to get some perceived training-benefit for some inconsequential event then your seriously misguided….and your response just provided a textbook example of why roadies mock triathletes…
@Chase – Let’s keep things friendly. People ride and train for different reasons. No reason to bash one reason over another.
Will this work without any cadence input at all? I’m inclined to guess it will not buy I would like a confirmation.
It works perfectly without cadence. Cadence (for better or worse) isn’t considered within the PowerCal calculations. For example, a couple days ago on the cruise ship I’m on I did a spinning class – no cadence sensor there, but still got power meter info.
Just curious, did you get to do any comparisons with Strava power estimates?
Not quite yet, it’s in my list of things to do though! I’ve actually got to go through and strip out the power info in the files so that Strava estimates instead of using that. My internet has been slow on the ship this week.
Hi,can you explain me what is the meaning of parameters A,B,C to calibrate power cal?
i made conconi test and the results are 183bpm for anaerobic threshold with 390w and 197bpm max with 440w.
the powercal showed about 275w at the threshold.
i try to change those parameters with the joule presets,and after the powercal showed more than 600w at 70bpm…
so,how can i adjust A,B,C in the correct mode to have the correct results?
thanks
How did you find the repeatability? In the end if the numbers are skewed, but skewed consistently, you can at least make some adjustments…again, not to replace a power meter, but to get people’s feet wet into the world of power. Thanks for the work.
Thank you for an incredibly in-depth review. While my tri coach had been encouraging me to get a power meter, I wasn’t ready to spend that kind of money. Based on your post I’ve gone ahead and purchased a PowerCal. My coach is very interested to see the data. I’ll share his thoughts over the next few weeks.
Stupid Question Time:
You mentioned that the power meter slowly climbed as you ran on a unchanging treadmill due to your heart rate climbing from lack of cooling.
That got me wondering about how much it raised? The body is still doing work as it tries to cool itself, certainly nothing that contributes to your running but it’s still work.
Could the PowerCal be a “whole body” power meter?
Not only is it counting your legs moving but the muscle action to keep your arms from swinging, your head up, and moving fluid around the body and out the pores to keep cool? ‘Cause in the end that’s all powered by the heart, right?
Which may make it less useful for specific action power (power to the pedals, power to the running shoe, etc…), but to me opens up a interesting new territory.
@Wayne, that’s called a heart-rate monitor….that is essentially what you just described.
True, and so is the PowerCal, but the BPM is not why it’s interesting.
Riding and testing for 2 months now with the powercal. ‘Calibrated’ it with a professional testing bike at our sport medical clinic for people with different FTP. Please mention below is only based on indoor testing.
1.I think the most important thing to find out is: how much does it under or over reads for your specific situation. Below may be a good guideline for using the powercal correctly. The good news is that it over or underreads, but from my experience ALWAYS in the same way. That is good for your own situation, but you cant compare it to other riders or other powermeters. But who cares? It works perfectly for setting up your powerzones and to get a 95-98% impression of your FTP!
2.FTP TESTING based on a 20 min max test shows and within a power profiling classification shows:
When your are very undertrained (<cat 5 rider) the over reading can be as high as 15-20 %
For a moderate (cat 4 rider) the over reading is between 10-12 %
For a good (cat 3 rider) the over reading is between 5-10 %
For a very good (cat 2 rider) the over reading is between 0-5 %
I think this covers the user group of the powercal. My FTP is 283 (powercal) – 10% = 255 (real world). I would suggest to repeat testing every month and also to calibrate first with your powermeter of medical test bike so you with what percentage % you should decrease the powercal FTP to get a real word value.
After all this, you can use the powercal perfectly for all P2, P3, P4 training + golden cheetah analyses. I would not recommend it for less than 2 minute interval training.
The secret of the powercal is that is uses HRV for its accuracy.
Good luck from Holland!
Very cool data points Wouter – thanks for sharing!
Thanks. In addition to my previous posting. More and more testing reveals that the cat 2 racer may find a under reading -3% So the new range would be : Minus 3% and plus 5% for a cat 2 racer.
Maybe it is good to give a few examples in which the powercal does not work properly to avoid some bad reviews. In my opinion it is very useful, when you have some backgrounds of the heart system and its stressors.
For example:
1. When it’s extremely hot (indoor +30 degrees) or cold ( <5 degrees) don't expect it to be very accurate because of a varied heart pattern.
2. When you are over trained, sick, or tired , don't expect too much. The ironic thing is that with a normal power meter, you will get a low average wattage and a high HF average. With the powercal, in same casus, you will get a high HF average AND a high wattage average. You may think, things are going well , but you are not! (very important point if using the PM index of Golden Cheetah or PM training peaks. The same for higher TSS, higher IF, etc.)
3. When drinking lots of coffee before cycling, your average wattage is not reliable. Same reasons as pointed at 2.
What i do to be sure that i will have a 'normal power cal' day is to monitor my rest HF. When it's normal (48) i train 100% by the data powercal is giving. When not: i am sceptical, but based on real facts as stated. The question is: how to use the product well and in what cases is it not reliable. When knowing this, it is really a great product.
hi ray!
first workout a few mins back, was supposed to do a 20 min test, i already paired it with my trainerroad tools, you are right the data did keep on jumping, being used to the constant power given the trainerroad(virtual) new to this as TR`s virtual power was what i have been only using. will it be fine if i use the ave power in my head unit which is just a node 1 instead of the current power? sorry if this is a dumb question but totally clueless. thanks and appreciate all the reviews!
Dennis
Thx for a great website and reviews
i have one question
i have a garmin edge 705 and garmin speed/kadence sensor. Can i just buy the heart strap and the powercal “communicates” with this sensor? or isnt it necesary at all? i mean if it only uses HR? i get confused since there selling it with a speed sensor to?
Simon
No need for the speed/cadence sensor from them. Early on, there was a tie-in there, but it’s not really there anymore, and thus really provides no additional value when it comes to wattage readings from the PowerCal. That all said, you can continue to use your existing GSC-10 sensor with the Edge 705 and this and all will be well.
so basicly i would get a new heart strap (powercals) and still get my HR and power from powercal, speed, cadence from the speed/cadence sensor (and the gps stuff from my 705)??
Essentially. Though, HR will also come from the PowerCal (two for one, HR + Power).
DC, love your reviews. I am a runner/cyclist, racer in both sports. Therefore, generally my HR values are lower on the bike during training, even during power intervals, unless I am racing. I had been using the Polar WIND wireless power meter with relative success the past 2 seasons knowing that my numbers were within +/- 5%, but recently wanted to get into the ANT+ market without blowing $1500 yet on a Cinqo. So I got the Garmin 800, Trek Duotrap for my new Madone, and got the Powercal based on your review that the numbers were basically in the ballpark. However, especially on the trainer, I notice the power numbers to be at least 100 watts low compared to my Polar, even on the high end during power intervals. I imagine that you are in considerably better shape than me so you would similarly experience lower HR values on a trainer or on the bike in general. But, your numbers seemed very close. Any thoughts on whether the calibration would be worth it? I would think that the calibration process would closer align power numbers to HR since it is comparing it to a powertap. Otherwise, it is time to save my money for the Cinqo. I want more accurate numbers than the Powercal. Any other tips for using the Powercal would be great.
Hmm, that is interesting. Calibration wouldn’t hurt. And since you have a power meter already, you could definitely do that. I’ve been trying to find the updated instructions for which numbers to input in for A/B/C. Been meaning to hit up the CycleOps guys. Sorry about that.
I’m still figuring out my PowerCal/Joule combo, but an important clue to the question (“am I getting fitter?”) might be, as stated in the manual that watts is a measure “..where work is equal to force times distance.” I haven’t been able to get the Joule paired to the HR strap for “watts” as I’m pairing it while sitting at the computer, not on the bike with the wheel spinning, so there is no speed value from which to make a calculation. Similarly, if, over time, I can ride at a faster speed with the same given heart rate (increase in force), PowerCal will report more watts, and I’ll know I’m getting fitter. It won’t work for runners, unless you can figure out how to get a speed value out of the sensor while running. I think. Maybe.
While using Virtual Power on Trainer Road (TR), and simultaneously recording Powercal’s data on a separate device, I found the power readings to be way off during intervals. The climbs and drops of Powercal data are not steady. That in turn makes the cadence and gear selection just as varied to match the power demand of each interval. Surprisingly, the average power from Powercal an TR were identical for a 90-min ride.
Powercal, like TR, are trials into training with a power meter. If that’s enticing, save up for a proper one.
I have a semi-related question/problem with the PowerCal and the Garmin GSC10 (Speed/Cadence) sensor. Both units are connected to my Garmin 910.
After I start my training session (on my trainer), when I stop pedaling I get a default cadence readout at 255. After I load my data to TrainingPeaks I have a very unattainable cadence that sometimes jumps up to 500. Obviously there’s a problem somewhere with Garmin’s interpretation of cadence after the Powercal is connected.
Do you know the answer to fixing this problem? Do I, more simply, buy the CycleOps Speed/Cadence sensor?
I’m more than the recreational athlete but much less than an elite. I don’t rely on power for workouts, only as a means to track semi-annual progression. So I’m ready to toss the PowerCal out the window!
Thanks for your great blogs, I’ve been following your posts for years!
Is the cadence fine without PowerCal? Otherwise, it sounds like perhaps either the battery is going on the GSC-10 (it happens, easy $3 fix), or, the magnet placement needs to be modified just slightly.
See here a response to this problem:
link to forums.garmin.com
I got this after reading the review because I wanted to see Power without spending lots of $$$. I don’t really know what I am looking at but it is fun and I am learning.
I think the PowerCal is absolutely amazing. The watts go to 0 when I stop pedaling. Not immediately but within a couple of seconds. When you watch the watts you would swear that it is using cadence, but they say it isn’t. I would never have thought my heart rate would be able to give out such fine details about what I am doing.
Thanks for all the reviews Ray.
Any idea if I can manually plug in my own values from my Quarq in the A/B/C rows? What does the A/B/C represent?
Hi,
A question related to the calibration process. The calibration phases are described as very easy, easy, moderate and so on. Do you happen to know the respective values given as percentage of the FTP? With those it would be much easier to calibrate the powercal: three minutes in 70%, three minutes in 80%, etc.
Hi,
If have been using a Powertap pro for 3 years now but only on my “summer bike”, i have purchased a Powercal Strap 2 months ago to use this during the winter. In my case for absolute watt numbers this device makes no sense at all.
However I’m actually not interested in absolute watts but I’m interested in a tool that improves my training. I have been using WKO+ and specifically the perfromance manager chart. As you know this chart is based on TSS which is based on the balance between actual power vs FTP. I suspect that when you establish the FTP using Powercal measurments than the TSS calculated (and as a result the PMC chart) will be pretty accurate.
Interesting stuff. So understanding the benefits of having estimates of power output while on the road…from a post ride perspective… how would you rate the quality of information produced by the Powercal to Strava’s power curve algorithm?
Is it waterproof? Can I wear under the wetsuit to be ready for the bike and run after the swim in a triathlon?
Yes, no problem using under a wetsuit.
In general where the weather hovers around 30-35 degrees celcius, will the Powercal still works? Or the pattern will be more varied? Due to the high temp I’m located at, my HR always shows around 160-170 on average, so will there use that as a baseline for calculation purposes, and determining any rate of change from the average to determine Power.
Yes, temperature has no bearing on it. It’s primarily change in HR, and rate of change that the unit is focused on.
Thanks for the review. Due to my remote work location and number of bikes i cannot use a powermeter for 2/3rds of my rides so on the basis of this review i purchased a powercal to try and bridge the gap. Somewhat for intervals but also for TSS. Before it arrived i assumed that the no calibration thing was a marketing decision rather than a scientific requirement. And i was correct, at stock calibration my measured power was 50% greater than powercal. I am am an average masters racer but larger than average (90kg) with a fairly high FTP.
After calibration it seems within 5% for any length of time drawing closer the more warmed up i am.
There are some issues with the calibration process though that make it hard.
1. Cycleops have removed virtually any mention of it and the only instructions i can find are your review.
2. You really need to do it on a trainer (learnt this the hard way) which if you have an inbuilt dislike of the trainer like me is hard.
3. My up to date poweragent always calculates “responsiveness” as zero (this is “C” when you transfer it to the powercal calibration). So i had to guess a number and i chose as close to 150 as i could get as this was the original. 150 exact is a bit of a problem as the slider is to picky and i could not get exact 150. Some explanation from the manufacturer would probably help. Note that without a value the power reading essentially is just tracking your heart rate.
So in summary. It can be a useful gadget but the calibration process is difficult on purpose with no help. I would recommend anybody with a powercal who can access an actual power meter to perform the calibration. I would like cycleops to provide a calculation for “C” or at least a discussion to allow us to make an informed guess.
Just gotten my Cycleops PowerCal. Anyone experiencing major spike issue in the heart rate? I tried using Garmin and CycleOps HRM Strap, and applied electrode gel, still having spikes. Temperature is around 33 degrees with high humidity. So should not be static.
Maybe this image might help.. link to oi48.tinypic.com
Eek, that’s weird. And, the upwards spikes don’t even match normal spiking issues. I’d ring up CycleOps support and have them swap the strap out for you. Their support group is rock solid and should get you fixed up in a few minutes.
Yes. I have the same problem with these 2-3 seconds spikes. I think that they appear from the sweat because in my workouts I don’t have any at the begining, just after an hour or so.
I’m thinking to buy another hr strap. Maybe the one from Polar but I don’t know if it’s compatible.
Hello!
I am considering on buying powerCAL. But I am concerned if it can be used for what I would like to use it
I am thinking on using it for two things, first 5 x 5min intervals on a short hill (with constant power) and for pacing myself on longer climbs (from 5km/450m to 15km/900m). With both of these trainings to keep up constant power, you will need higher HR with time (each interval), for example at the start of a long climb to pedal 300W ones HR would be 175bpm, and after 30min of climb, to still put out 300W ones HR would be over 180bpm.
How does powerCAL deal with such riding, can I pace myself on longer climbs with it?
Thanks
Aleksander
Well, just got a powercal (my older garmin HR montior died) and powercal was just $30 more in Canada, so it’s nice for the added feature for when I had a rented bike, or go for a MTB ride without a powermeter.
I was surprised actually at how close it was for average on >5 minute efforts against my quarq, but still would like to have it “fine tuned”.
Has anyone had success connecting the PoweAgent using the Garmin stick, with windows 8 or a Mac? The stick is working fine (works fine downloading workouts and with trainerroad). But there is no way I can get it to work to configure the powercal, it does not find the powercal.
Has anyone experienced similar?
I connected using the suunto stick that this website recommended. Make sure you activate it first by either putting it on or rubbing the HRM strap pads with the transmitter connected to the strap. Can’t stress enough how important it is to use a trainer and try to make it as close to the instructions DCR has above. Good luck.
Rafael,
Did you have any luck figuring out the calibration?
I am having the same issue. Ride analysis is good. New values set in my user profile just fine. But when I select the values and try to save to the PCal, it just sits there thinking forever, eventually giving me a Java error message. I am using the Suunto stick, and the strap is active. Computer is a Macbook running 10.6.8.
Frustrating, as the PCal numbers are 40% higher than my PowerTap.
I’m not sure if I am misunderstanding the calibration instructions, but does one record the ramp test with both the powercal and another power meter? Or do you simply use the direct force tool to record the test and then use data from that to write back settings to the powercal?
You do the ramp test with a head unit recording power from a direct force powermeter and HR (I used quarq and an edge 500). Open that workout file on Power Agent (ok until here), the PowerAgent analyzes the file (ok) and then defines new coefficients (ok) to be sent to re-configure the Powercal (where it fails).
Sending the coefficients is the part it is failing . It does not seem to reach the powercal for some reason. Garmin Ant+ agent is closed, no other software or service is using the usb ant+ stick, ant the powercal is awake (i had it on and it is streaming HR data to the Garmin Edge).
It sounds as if the drivers for the ant+ stick are not working correctly. Can you verify it with another device. Try different usb ports.
Will it work with a Forerunner 305 fro Garmin?
No, the FR305 doesn’t support power meters.
It does however support the heart rate strap piece of it though, so that portion will work (but in that case, you might as well save $60 and just go with a regular HR strap).
Thank you looks like I might have to go for the more expensive package.
RE: Powercal and latest Garmin Soft Strap
I’m having trouble getting the Powercal to work and pick up actual readings on my 910xt when using the Powercal unit with the Garmin Soft Strap (newest version).
Any suggestions?
Is it not picking up anything, or just wonky readings?
It’s literally not picking anything up – really strange. I played around a bit and “flipped” the Powercal so it’s “upside-down” when connected to the strap – no success =(
Everything looks to be attached pretty solid – it detects the HR monitor and the Powercal with the correct serial # but the readings don’t register.
I wish it were just wonky readings =(
For those looking at spare / replacement straps.
Powercal with Polar soft strap. I have used the powercal successfully with the garmin soft strap. The powercal seems incompatible with the polar strap however (even though the garmin transmitter is compatible). There is something slightly different about the holes that the transmitter plugs into on the polar strap. The powercal transmitter pops straight out.
Quick update on my non-working Garmin Soft Strap [when using Powercal]:
I used/took my lady’s Garmin Soft Strap and tested the Powercal combo…and it worked =(
I then tried to get my Garmin transmitter and Soft Strap combo to start working again and it doesn’t work anymore =( I even tried using the electrode gel and it keeps cutting out and giving me readings of “0″
Any suggestions?