DC Rainmaker

Power Meter Pedal Shootout: Vector 3 vs PowerTap P1 vs Assioma

Over the course of the summer we’ve seen both Garmin and Favero roll out new pedal power meters.  In Garmin’s case they’ve got their third generation Vector 3 pedals, while in Favero’s case they have their Assioma units, which are effectively 2nd generation BePro pedals.

Meanwhile, PowerTap has had their P1 pedals in the market for over two years now – effectively raking in the cash over their competitors.  All for a single reason: Simple install requiring no complex tools.

And that’s really the reason for this post.  We’re at a point now where Vector no longer requires funky tools, and Favero no longer requires an even funkier installation process.  Vector also ditched the pods too.  All three units can be installed in under 60 seconds, faster if you’re motivated.

But there still are many nuances to each of the pedal platforms, and many of you have asked for a more detailed look into those nuances.  So with that, let’s dive down the rabbit hole!

Sizing:

First up we’ve got the weights.  There’s no real reason to belabor this point, here’s the weights of each pedal, and then the total set of pedals.

 

 

 

For each one I excluded spacers, since not all cranks/pedals require that.  For fun, here’s the weights of the spacers.  I just weighed one spacer from each, but obviously you need either one or two per pedal, again, depending on your cranks.

Next, here’s how they look side by side.  First, front on:

Next, spindle-side:

Then the other side:

And finally, the rear:

To state the obvious, the Vector 3 is the slimmest of the bunch from a sizing standpoint, and the P1 the chunkiest.  The photos otherwise kinda speak for themselves.

Installation:

The biggest drawing factor for all three of these units is the installation.  All can be installed in under 60 seconds, or removed in under 60 seconds.  And all can be done with small tools that can be easily travelled with.

When it comes to the type of installation, there’s basically two camps here.  For the PowerTap P1 and Favero Assioma pedals, you’ll use an 8mm Allen key (hex wrench).  This is found the world around.  Here’s two examples, one in a small form factor, one in a larger form factor:

I’ve used the smaller one above countless times to install the PowerTap P1 on bikes in hotel rooms on almost every continent on this planet.  Removal-wise, certainly a larger tool is better, but you can make do with the smaller one.

For the Garmin Vector 3, you’ll need a standard pedal wrench (15mm) to install.  Note, not a torque wrench.  Just a standard pedal wrench like many other pedals need.  Here’s a big and small version of that:

What’s notable here is that small pedal wrench I found on Amazon (below).  I’m really excited about that one since it allows me to travel with everything in a small Ziploc bag.  Whereas a big pedal wrench might not be allowed in carry-on luggage (I like to travel light).

 

No matter which one though – all of these are silly easy to install, as seen above.

Now, a quick note on calibration.  All three units support basic zero offset calibrations, however, they provide slightly different results, which can be interpreted different ways:

Garmin Vector 3: When doing a zero offset, you’ll get a torque value, allowing you to place weights on the pedals if you’d like to manually verify the torque value.

PowerTap P1: When doing a zero offset it’ll show you a current status value that floats based primarily on temperature, within an acceptable range.  This is valuable to determine if something is going askew.

Favero Assioma: When doing a zero offset it’ll show you simply a success or failure message.  You cannot see any shifts within a successful unit.  So it’s kinda all or nothing here.

Finally, what about settling. In my testing, all three power meters can be installed on a bike and used immediately without multiple rides for settling (as has been the case in some previous power meters).  Still, I recommend doing 2-3 quick sprints of 4-8 seconds to ensure everything is tight.  Then do a zero offset.  Doing so, in my experience with all three units, will give you perfect results.  Note, I’m only referring to the first time you install the units on a given bike.  This entire settling process can be completed in under 30 seconds.

Factors and Stacks:

In the IT industry one says ‘rack and stack’, but that didn’t really make sense for the title here, because there are no racks.  Just Q-Factors, Stack Heights, and other measurement focused things.  I think this category – more than any other – is full of specs that people think they care about, but don’t actually care about in the real world.  We’ll start with the prime example of that, Q-Factor.

Q-Factor:

Q-Factor refers to the distance between the centerline of the pedal and the end of the threaded portion.  Below, is an example of the q-Factor from Favero, and for a single side.  Often times this is also represented on a bike as the distance between the threads on the crank arms (both sides).

A lot of people get really bent out of shape about q-factor, but then forget that the different bikes they have in their garage for different aspects of cycling all likely have different q-factors.  For example, a road bike has a q-factor generally of ~150mm, while a mountain bike has a q-factor of 170mm.  Jump on that WattBike?  It’s got a q-factor of 173 but the Atom is 160.  But wait, your gym spin bike has a different q-factor, and that’ll vary by brands and models too.  Schwinn’s AC Performance is 170mm, while Keiser’s M3 is 197mm.

Not to mention that the handful of studies that have looked at q-factor basically all said that there’s a slight short term impact to switching distance of q-factor, but then like anything else your body adapts.  That’s no different than any other bike component.

Still, there may be specific medical reasons why you want to keep things similar.  Thus, here’s where you stand on q-factor:

Garmin Vector 3: 53mm (55mm with spacer)
PowerTap P1: 54mm
Favero Assioma: 55mm

And for photos, if you look at them from the side atop a standard Look Keo pedal:

  

One caveat to this, is that the q-factor will change by up to 1-2mm depending on whether or not you use spacers, which in turn depends on your specific crank arms.  For example, Vector doesn’t need spacers unless the pedals push through too close to the chain.  The PowerTap P1 doesn’t need them on aluminum cranks, but does on carbon.  And Assioma needs them if your crank arms have a slight indent in them where the pedal attaches.

Cornering:

Next, we’ve got the impact of stack height on cornering.  This gets to whether or not your crank arm would hit the ground while making a tight corner, likely in a race.  Specifically, this is if you pedaled through the corner, and/or had stupidly placed your crank arm down on the side closest to the corner.  The concern grows greater with longer crank arms, and is less of a problem with shorter crank arms.

This was a fun one to measure.  In my case, I’m running 175mm crank arms, which is slightly longer than the ‘average’ of 172.5mm crank arms.

In order to measure this, I placed the arm straight down, and then measured the angle in which the bike would have to go in order to hit the ground.  I used an iPhone with a level app that I validated first on a level surface.  Then I trapped it in between the water bottle holder and validated it showed level as well.  Next I tilted the bike until the centerline of the pedal touched the ground.

Because I only had two hands (one to hold the bike, one to hold the camera), I couldn’t get the photo of it touching the centerline (I measured before I took the photo).  Also, I tethered the bike to a table via cable so I could lower it down slowly.

  

In any event, here’s all three:

  

I was somewhat surprised to see Vector 3 slightly bigger (29° vs 27°), so I did it twice more.  But it shows you the impact of the spacers/washers.  For both the PowerTap P1 and Assioma, I needed spacers.  But with the slightly different design of the Vector 3, I didn’t need spacers, thus, it was ‘closer in’ to the bike and had more angular potential.

Now, keep in mind, these are really steep angles:

I showed this same thing in the PowerTap P1 review, and to date I’ve seen only one person state they’ve hit their pedal on the ground while cornering (to which someone else immediately pointed out they’d probably have hit that pedal anyway, regardless of the slight increase in stack height).

Now you may be asking – what’s a normal pedal?  Well in measuring the same Look Keo pedal you saw up above, I managed to get it to 35° before it touches, so an addition 6° beyond anyone else. Why?  Because the side of the Keo pedal spindle tapers inwards, as opposed to all of the other pedals have basically flat-sides of the spindle.

Thus how they get more breathing room while cornering.  On the other power meter pedals, these spaces are packed with electronics.

Stack Height:

Speaking of stack height, this is the measurement of the center of the spindle to the bottom of the shoe.  This is actually a really tough one to measure myself, due to the slight ups and downs of the pedal.  So instead I reached out to all the companies to get the official stack height numbers.  They are as follows:

Garmin Vector 3: 12.5mm
PowerTap P1: 14mm
Favero Assioma: 10.5mm

Cleats:

So I’ll tell you a funny story.  When the PowerTap P1 pedals came out, it was noted by myself and others that the P1 pedals required slightly different cleats (made by Xpedo, included in the box) in order to get a perfect clip-in.  For some people, regular Look Keo cleats worked just fine.  And even for me, if I had new Look Keo cleats, all was well.  But if I had older/more worn Look Keo cleats, then I’d have pop-out issues.  A bunch of folks got really caught up on this.

Then, fast forward to the Favero BePro pedals.  They too also used the exact same Xpedo cleats.  Same with the new Assioma pedals.  I noted the cleats, but didn’t talk about it as much (for no particular reason).  Nobody talked about it.  Seriously, nobody cared.  I don’t know why – but I found the contrast interesting.

In any case, both the PowerTap P1 and Favero Assioma pedals use the same Xpedo cleats, both of which are included in the box.  And in both cases, if you’ve got relatively new Look Keo cleats they’ll probably work just fine.  With Garmin Vector 3, they use Look Keo cleats as-is, with no additional requirements.  They also include a pair in the box too.

Note that Vector 3 does not support the Shimano swappage kit that Vector 1/2 did.  Maybe down the road, but nothing in the cards today.

Float:

Just a quick note that float is actually determined by the cleats you use, and not the pedals themselves.  In the case of all three companies, you’ll get red cleats that have 6-degrees of float in them.  You can also buy grey cleats that have zero float in them.

Max Rider Weight:

Lastly, some pedals are limited in terms of how heavy the rider can be.  Of course, there’s not truly a rider weight limit, but rather an output wattage limit.  Except making that clear to consumers would be a nightmare.  So instead they do math backwards a bit since in general heavier people can output more power than lighter people with the same amount of effort.

Now there’s really two aspects at play here.  First is the safety-focused aspect of the pedals breaking.  But that’s not really of concern here, these pedals are pretty much fine for anybody in the ballpark of these weights.  For these companies the real issue is breakage of the sensors within the pedal above a given threshold.  Here’s the stated max rider weights:

Garmin Vector 3: 105 kg (231 lbs)
PowerTap P1: No practical limit according to PowerTap
Favero Assioma: 120 kg (265 lbs)

With that, let’s talk tech.

Tech Specs:

Next we’ve got various tech specs that didn’t fit anywhere else, mostly on the electronic/transmission side.  First up is how the darn things are powered.

Battery:

Each of the three pedals uses different battery options, along with different power outputs.  To simplify this, here are the three models:

Garmin Vector 3: 4xLR44 (two per side) coin cell batteries
PowerTap P1: 2xAAA (Lithium, one per side) batteries
Favero Assioma: Rechargeable battery, encased, not swappable

And for those loving pictures, I got pics of all that goodness too:

As for battery life, you’re going to have to go with claims here as the standard.  I can say that I believe the Favero batteries are in the ballpark of the claims, as are PowerTaps.  I haven’t put in 125hrs yet on a single set of Vector 3’s to know for certain.

Garmin Vector 3: 120 hours (dual ANT+/Bluetooth Smart), 150 hours (just ANT+)
PowerTap P1: 60 hours
Favero Assioma: 50-65 hours

Now, when it comes to rechargeable batteries, some have concerns.  I’m going to quickly copy/paste what I wrote in the Assioma review below. But ultimately it’s just a personal preferences thing.  The connector on the Favero Assioma is a million times better than the non-awesome micro-USB connector on the Favero BePro units.

From the Favero Assioma In-Depth Review: I’ve seen some concern about what happens when the batteries ‘die’, apparently in reference to how you might swap them out.  Some of this is due to misunderstandings about how rechargeable batteries die.  First off is that batteries are generally rated to a certain number of recharge cycles, in the case of the Assioma battery, that’s estimated to be about 500 cycles (per an e-mail from Assioma).  Once it reaches that number, they don’t stop working.  Instead they might slowly degrade, perhaps to 80% of battery capacity.  With a battery life of 50 hours, and the 500 recharge cycles, that puts you at 25,000 hours of battery life before it starts to degrade.  That’s 24 years of riding 20 hours per week.  Or almost 50 years if you rode 10 hours per week.  Seriously, you’ll have long moved onto something else by then.  Battery cycle time is not your concern here.

Status LED’s:

All three units contain status LED’s that allow you to validate basic operation.  These lights are also used for things like firmware updates and such to let you know what’s going on.  On the Vector 3 you can see it at the end of the spindle (green light), on the PowerTap P1 the green light is to the left on the pedal body, and on the Assioma it’s around the pod.

Basis ANT+/Bluetooth Smart Connectivity:

Next is how and what each unit transmits, starting with the most basic things in this mini-section, and then moving to the more complex stuff in the next mini-section.  Simply put, all three units broadcast all the same core fundamentals. They all broadcast the following data via the ANT+ & Bluetooth Smart standards:

ANT+ Total Power
ANT+ Power Balance (Left/Right)
ANT+ Cadence (RPM)
ANT+ Torque Effectiveness
ANT+ Pedal Smoothness
Bluetooth Smart Total Power
Bluetooth Smart Power Balance (Left/Right)
Bluetooth Smart Cadence

There are no official standards for Bluetooth Smart Torque Effectiveness or Pedal Smoothness at this time.

When it comes to head units, within the core settings above, all reputable head units support all these different items.  One caveat though is Bluetooth Smart-only head units can be a bit more tricky, as often times they’ll only pair to a single side of a dual sided power meter.  For example, Suunto Spartan series units can only connect to either the left or right side, not both.  As such, you’ll get one side doubled (in which case you might as well just save a boatload of money and buy a single sided power meter).

As a general rule of thumb, most in the power meter industry would recommend using ANT+ over Bluetooth Smart when connecting to your head unit, despite the unit broadcasting both.  The exception to that being if you experience drop-outs from your power meter to head unit (none of the units here though are prone to that), in which case you could try to see if Bluetooth Smart will resolve the drop-outs.

Of note is that metrics like TSS (Training Stress Score), NP (Normalized Power), and many others are not at all power meter model dependent.  Rather, they are dependent on the specific head unit and/or training platform you use.

(Note: Minor technicality is that Vector 3 won’t quite yet broadcast on Bluetooth Smart, that’s slated for no later than mid-October.  But Garmin states that’s a hard-stop date, as they want to be there for the indoor trainer season and broadcasting to tablet/phone based trainer apps.)

Advanced Pedaling Metrics:

Now in addition to core power metrics seen above, two of the models have different advanced metrics that can be shown.  These include Garmin’s Cycling Dynamics platform, as well as PowerTap’s advanced pedaling metrics. I’ll briefly run through both (Favero does not have any such platform/app/etc. at the moment).

PowerTap P1 Metrics: In the case of PowerTap you can leverage the PowerTap Mobile App to get additional metrics that are not available on a normal head unit.  These metrics specifically include the Force Vector, which shows the angle and amplitude of the force – in newton’s and placement on the pedal stroke.  In addition, you’ll get a plot within the app of where your pedal stroke is heat-map style.  The only challenge with these metrics is you have to have the app running to see them, and there isn’t any method to export/save the data.  Full details in this post from them.

Note that PowerTap has been working with some bike fit companies though to incorporate metrics in their products, though that won’t really help you as an end consumer.

Garmin Cycling Dynamics: Of course, the behemoth in advanced power meter pedal metrics is Cycling Dynamics.  Unlike PowerTap, these metrics are displayable on a head unit (albeit at present, only Garmin’s) as well as later on in Garmin Connect.  Further, 3rd parties can also display the data too (WKO4 does today).  These metrics span a wide number of areas from platform center offset to seated/standing time.  Some of these metrics can be used in bike fit, while others are clearly more geek-oriented.

For example, I can tell you my max and average power for both while I’m seated versus standing.  There’s likely something to be learned from that, but mostly it’s just a fun geek stat.  Whereas aspects like PCO (Platform Center Offset), could be useful for looking at whether or not your bike fit is proper.

In total there’s a massive list of Garmin Cycling Dynamics metrics that you can add/record.  They are:

PCO, PCO – Avg, PCO – Lap, Power Phase – L, Power Phase – L. Avg, Power Phase – L. Lap, Power Phase – L. Peak, Phase – L. Peak Avg, Phase – L. Peak Lap, Power Phase – R., Power Phase – R. Avg, Power Phase – R. Lap, Power Phase – R. Peak, Phase – R. Peak Avg, Phase – R. Peak Lap, Time Seated, Time Seated Lap, Time Standing, Time Standing Lap, Average Power Standing, Max Power Standing, Average Power Sitting, Max Power Sitting, Average Cadence Standing, Max Cadence Standing, Average Cadence Seated, Max Cadence Seated.

Phew. Again – at present these are only available on Garmin head units, so if you’ve got something like the Wahoo BOLT, you’re outta luck here for recording the advanced data.

Power Accuracy:

I added this as a specific section since I’m sure many will ask about it.  At this point, when it comes to accuracy, all three units deliver where it counts.  You can see this within my PowerTap P1 in-depth review, as well as my Favero Assioma in-depth review.  Given the Garmin Vector 3 pedals are in the final stages of firmware, they are still finalizing things.  But accuracy of the power numbers isn’t something I’m having any issues with.  So all look good there.

Note that officially each company makes slightly different accuracy claims:

Garmin Vector 3: +/- 1.0%
PowerTap P1: +/- 1.5%
Favero Assioma: +/- 2.0%

Note that I’ve seen some older posts/pieces/videos referencing PowerTap P1 accuracy issues, specifically on climbs.  This was solved almost two years ago in a firmware update.  Similarly, I’ve also seen some tests people did with Q-Rings on the PowerTap P1 in the first few months.  Ironically, these tests I’ve seen were done compared to other power meters that didn’t support them.  There are certainly quirks of the P1’s that people have complained about over the years, but accuracy simply isn’t one of them these days (nor has it been for a long time).

As for q-ring/non-round rings/oval rings at large, the only pedals that officially support them is the PowerTap P1 (they didn’t upon launch however).  Neither the Favero Assioma or Garmin Vector pedals will give correct/accurate power numbers.  They won’t be horribly far off (2-4% in most cases), but they won’t be accurate either.  Again, at that point, you might as well buy many cheaper solutions (even single sided) and save the money.

Price, Single Sided Variants:

When it comes to price, you’ve got a bit of a range:

Favero Assioma: $799
PowerTap P1: $999
Garmin Vector 3: $999

Note that the PowerTap P1 pedals were dropped in price from $1,199 later the same day after Garmin announced their Vector 3 pedals at $999.

Obviously, I think the Assioma price is superb.  It’s a very good deal, no questions about that.  And I think the Garmin Vector price is fair, given the reduced size and lack of pods compared to the other two.  Not to mention the far more detailed analytic metrics of Cycling Dynamics.

It’s the PowerTap P1 price that I’m not sold on.  While they obviously have inventory in the market (whereas Garmin will probably be supply constrained for at least a few weeks, maybe a month), the P1 is simply a less desirable product now compared to Vector 3.  Whether it be size or weight, or the metrics it transmitted.  I would have thought $899 would have represented a fair price for the P1 at this point.  It’s ‘more’ than Assioma from a functionality standpoint, yet less than Vector 3.  Like the whole bears and porridge thing.

Note, for lack of anywhere else to put it, all three companies have single-sided variants (PowerTap P1S, Garmin Vector 3S, Favero Assioma Uno).  This simply means they give you a power sensing left pedal, and then an empty right pedal.  The left pedal’s power is just doubled.  No magic here at all.  It’s essentially the same scenario Stages pioneered years ago with crank arms.

My guidance would be that if you feel like you’re going to upgrade to the dual solution down the road (all companies enable that), then go forth.  However, if that’s not the case, and you’re not buying for portability/transfer reasons, then I’d probably save the cash and just go with a single-sided crank arm solution (I.e. Stages, 4iiii Precision, etc.…).  Alternatively, I’d look at doing proper total power instead of a left-only solution via something like the Power2Max NG ECO, Quarq DZero lineup, FSA PowerBox, PowerTap C1, or similar.  Proper total captured power (but not dual left/right split) is ALWAYS better than just left-side only doubled.  Always, always, always.  Anybody who tells you otherwise should be kicked in the balls*.

(*Don’t even get me started on the whole Froome argument, he hasn’t used a left-only unit in three years.  He’s been riding Stages LR dual-sided for a long time.)

Comparison Tables:

I’m not entirely sure at this point why I’m even including the comparison tables, other than for your graphical consideration since my power meter database doesn’t even come close to having all the random specs seen here.  The above post details more data points than the comparison tables do, but perhaps this will make it a bit clearer in case you got lost in my fog of text and photos.

Function/FeatureFavero Assioma PedalsGarmin Vector 3PowerTap P1 Pedals
Copyright DC Rainmaker - Updated November 2nd, 2017 @ 7:39 amNew Window
Price$519/$799 (single/dual)$999$999
Available todayYesShipping Late SeptemberGlobal
Measurement TypeDirect ForceDirect ForceDirect Force
Attachment areaPedalPedalsPedals
Attachment limitationsLOOK KEO COMPATIBLE PEDALS ONLYLOOK KEO COMPATIBLE PEDALS ONLYLook Keo variant cleats only
Weight (additional/net)150g per pedal (inclusive of pods)161g per pedal216g per pedal
Wireless Connectivity TypeANT+/BLUETOOTH SMART (DUAL)ANT+/BLUETOOTH SMART (DUAL)ANT+/Bluetooth Smart (Dual)
Unit auto-turns on when on bikeYesYesYes
BatteryFavero Assioma PedalsGarmin Vector 3PowerTap P1 Pedals
Battery Life50 Hours120-150 hours60hrs+
User or Factory battery replacementN/AUserUser
Battery typeUSB RechargeableLR44AAA
Low Battery WarningYesYesYes
FeaturesFavero Assioma PedalsGarmin Vector 3PowerTap P1 Pedals
Measures/Transmits CadenceYesYesYEs
Ability to update firmwareYesYesYes
Transmits Left/Right Power Balance (Measured)YesYesYes
Transmits Pedal SmoothnessYesYesYes
AccuracyFavero Assioma PedalsGarmin Vector 3PowerTap P1 Pedals
Measures all power outputYesYesYes
Claimed Accuracy Level+/- 2%+/- 1%+/- 1.5%
Includes temperature compensationYesYesYes
Supports auto-zero functionYesYesYEs
Supports manual calibrationYesYesYes
Supports hanging weights (static test)-YesNo
SoftwareFavero Assioma PedalsGarmin Vector 3PowerTap P1 Pedals
Phone App to Configure/TestYesYesYes
PurchaseFavero Assioma PedalsGarmin Vector 3PowerTap P1 Pedals
Amazon LinkN/AN/ALink
Clever Training - Save a bunch with Clever Training VIP programLinkLinkLink
Clever Training - Save a bunch with Clever Training VIP programLinkLinkLink
DCRainmakerFavero Assioma PedalsGarmin Vector 3PowerTap P1 Pedals
Review LinkLinkLinkLink

Phew!  Note that you can compare any other power meter you’d like within the product comparison tool here.

Wrap-Up:

Phew.  Seriously, I didn’t expect this post to be this long.  Sorry, not sorry.  I started off with what was going to be an innocent little product comparison table post, and then it spiraled out of control.

Here’s the thing, nothing I say in this summary is going to cover what the previous 7 or so sections didn’t already cover.

But what I can tell you is that all three of these pedals are solid, and I’d be happy to use any of them.  Certainly, they each have their own minor pros and cons.  Be it price, size, transmission specs, or otherwise.  But at the end of the day, I can take any of these sets of pedals in a single plastic baggie with me while traveling, and easily attach them to any bike on this planet (or at least, any bike I’d want to ride).  And I can do so in under 60 seconds and be riding immediately and with power I’d trust.

And honestly, that’s what it’s about.  Find the pedal solution that works for you and your specifications, but all of these are good options.  To dig deeper into any of the three units, check out the full in-depth reviews or posts below (full review soon for Vector 3, once final firmware is achieved).

  

With that – thanks for reading!