Favero Assioma Pro MX MTB (SPD) Power Meter In-Depth Review



Favero has finally officially announced their new SPD Favero Assioma variant, called the Favero Assioma Pro MX-2 MTB. I say ‘finally officially’, because the unit was actually non-announced back in November or so on their site. And that followed a year or two of teasing about it. And even when it showed up on their site back in November, it was only for Italian folks to order in a public beta.

But, as of today, anyone can buy one – and it unquestionably delivers the biggest bang for your buck for an SPD-based pedal power meter, or for that matter, any pedal-based power meter. In this review, I’ll dive through my usage over the last few months, including plenty of accuracy testing, new features, and more.

Finally, note that this unit is a media loaner, and once this review is complete, it will go back to Favero. As always, I don’t accept advertising from any company I review – so, if you found this review useful, consider becoming a DCR Supporter, which gets you an ad-free site, plus the behind-the-scenes video series between both myself (and my wife) on everything that happens in the DCR Sports Tech Cave/universe.

What’s New & Key Specs:

The Favero Assioma Pro MX-2 power meter pedals will be familiar to many, due to the Favero Assioma brand lineage. However, under the covers, there are actually a number of changes – some quite significant. So while it shares the Assioma name, I’d probably think of this as an entirely new product. Some of it is clear now, and some of it coming down the road.

The key differences to the existing Favero Assioma pedals are:

– Added SPD cleat type (previous was LOOK KEO and SPD-SL)
– Got rid of battery/communications/charging pod entirely. Everything is inside the spindle now
– Added Platform Center Offset (PCO) within the cycling dynamics suite of metrics (previously they couldn’t get that specific item, while already having other cycling dynamics metrics).
– Changed battery life to 60 hours (Favero Assioma Duo is claimed at 50 hours)

Favero says they spent significant amount of time to entirely redesign the full spindle, seen below, such that the battery and connectivity aspects happen deeper in the spindle, rather than closer to the crank arm. As such, they believe they’ve reduced the chance of power dropouts and other power connectivity issues that might occur from impacts. Additionally, they’ve made it “easy” to swap out the spindle in the event of maintenance or failure. The downside though, is that the battery takes up nearly half the available space, and as such, has a fair bit lower battery life than their SPD power meter competitors.

Of course, there’s a ton more that comes with the off-road focused SPD form factor around build quality and such, but we’ll dive into that in other sections.

Let’s then step back and just cover the quick top-level specs of the Favero Assioma Pro MX-2 MTB power meter:

– Claimed accuracy: +/- 1% (0-3,000w)
– Temperature Compensation: Yes – active temperature compensation
– Auto-Zero Capability: Yes
– Manual Zero-Offset Capability: Yes
– Connectivity: ANT+ (unlimited concurrent connections), and Bluetooth Smart (three concurrent connections)
– Cadence Transmitted: Yes (10-250rpm)
– Left/right Balance Transmitted: Yes
– Cycling Dynamics (or similar): Yes, full suite
– Oval/Q Chainring Compatible: Yes
– Weight per pedal: 191.4g (per pedal)
– Battery type: Rechargeable
– Battery life: Claimed 60 hours
– Water Resistance: IP67
– Operating Temp Range: -10*C to +55*C
– Max Cyclist Weight: 120kg
– Q-Factor: 53mm
– Stack Height: 11.2mm

Note that Favero is selling the pedals in two versions: Dual-sided and single-sided. The pricing is as follows:

Dual-sided: $750USD/614€+VAT (e.g. on average about 750€ including VAT)
Single-sided: $499USD/368€+VAT (e.g on average about 450€ including VAT)

Also of note to those who plan to somehow kill their pedals, is that Favero’s replacement pedal body (the not-smart pedal piece that surrounds the spindle housing the smarts) is a mere 49EUR per pedal, which is substantially cheaper than Garmin’s 199EUR for a set of two. That despite the fact that Garmin’s is made of metal+plastic, whereas Favero’s is all metal.

In the Box:

I’m always fairly impressed at how well-executed most power meter pedal boxes have been over the years. Be it Favero, Garmin, PowerTap, SRM, and more. They’ve always been pretty solid, and this is no exception.

If you remove the booklet above, you’ll find a small brown baggie of all the mounting hardware (for your cycling shoe), as well as all the various parts carefully laid out below.

Above you’ll see:

1) Two charging plugs (they attach to a Micro-USB cable I’ll show below)
2) Four spacers/washers (in case you have frame clearance issues)
3) One set of cycling shoe mounting hardware
4) One tool-set (two pieces) for removing the pedal body/spindle in the event of maintenance/support
5) The two pedals themselves (still in the box)

Then, if you take those two pedals out, in that same box you’ll also find a very long dual-ended micro-USB cable, seen below here along with the pedals, warranty information, and a quick install guide.

And finally, here’s a closer look at those pedals:

And for funnies, the edge of the pedals (spring) close-up:

With that, let’s move into getting them installed and set up.

Note: The first set of pedals I received in December, which fell under the company’s Italian public beta period, did have one manufacturing defect – it was missing the four screws that held the upper portion to the lower portion of the pedal. Meaning, it fell apart roughly one pedal rotation into riding with it (indoors, thankfully). Favero had warned that they were working through QA issues in the factory still, and thus I’d be exceptionally surprised if that slipped through the cracks in the three months since. Assuming I don’t hear of other similar things in the coming months, I’ll likely remove the section by summer or so. Favero is well known for their quality, and thus I wouldn’t be too concerned about this initial beta teething period thing.

Install & Setup:

Probably the biggest benefit of pedal-based power meters (compared to other forms) is the speed of installation. It’s the exact same as installing any other pedal – quick and simple. The only added item here is a one-time activation, and, if you change the crank length of the bike you’re installing it on (e.g. from one bike with 170mm cranks to another bike with 175mm cranks, then a quick update of that setting).

In any event, you’ll simply install the pedals using a pedal wrench onto your crank arms. Ideally, you’d add a tiny bit of grease if you’re feeling generous. From a torque standpoint, while Favero does specify the required torque, you’re basically looking at ‘rather snug’, but not ‘gorilla tight’.

Pedal-based power meters do need to be snug though, because if they’re loose, they won’t be accurate. However, pedals will automatically tighten as you pedal. Thus, standard practice is 2-4 nice solid sprints to get everything nice and tight (this is true even if you torque them to proper spec).

With that set, you’ll open the Favero App to get the pedals activated for the first time. This process will also offer firmware updates as well.

Once activated, it’ll walk you through a quick wizard of how to calibrate (zero offset) your pedal. Additionally, you’ll see the option to set your crank length. For pedal based power meters, you must set the crank arm length. That’s found just inside the crank arm (where the pedal gets inserted in). It’ll be listed as a value typically between 160mm and 175mm, but can be lower/higher. The most common is 172.5mm, which is the default set for the Favero Assioma pedals.

In addition to setting this in the Favero app, you can also set it via other bike computers (e.g. Garmin/Wahoo/etc), as well as some watches. However, not all apps (e.g. Zwift) will support crank lengths, thus it’s important to set it via the app anytime you move pedals to a bike with a different crank length.

With that all done, you can ignore this section again and instead, we’ll look at daily ride usage.

Daily Ride Usage:

From a riding standpoint I’ve been testing it across MTB, gravel, road, and…well…beach (however you want to define which category that should be put in). Generally speaking when it comes to MTB-focused power meters, the main thing you’re looking at is durability, along with accuracy. I touch on accuracy a bit later.

However, those two aspects aside, the data displayed from the various ride types are the same. Thus, with everything all configured it’s time to pair it top to your bike computer or watch (or app). The Favero pedals have both ANT+ & Bluetooth Smart, and allow multiple concurrent connections on both fronts. This essentially means you’ll be able to pair it to pretty much any device that can talk to a cycling power meter.

In my case, over the last few months, I’ve tested with Garmin Edge units, Wahoo Bike computers, Apple Watch, and validated enumeration in both Zwift & TrainerRoad. I’ve probably tried a few other things too, but have already forgotten. Either way, it uses industry-standard protocols, so connectivity shouldn’t really be an issue here.

As an example, on a Garmin Edge device, you’ll search for a power meter. You’ll want to connect via ANT+, rather than Bluetooth, else you won’t get the cycling dynamics information. That’s because cycling dynamics, as well as other bits like pedal smoothness and torque effectiveness, are only over ANT+, and not Bluetooth (that’s also of note if you have a Suunto/Polar watch because you won’t see that information).

Once paired, you can name the power meter however you’d like. Also, you can set the crank length here and it’ll be saved, in case you’re swapping bikes.

Further, you can enable the full set of cycling dynamics info here, as well as check firmware versions and battery:

Now on most power meters, you’ll want to calibrate (zero offset) at some point towards the start of each ride. I say ‘towards the start’, because this is really about ensuring no load is on the pedal, as well as ensuring any big temperature shifts have happened (such as taking the bike from inside to outside in the winter). Generally speaking, I’ll just stick my bike outside for 10-15 mins as I get my cycling stuff ready. But of course, not everyone can do that location-wise. The next best thing is to then calibrate about 15 minutes into your ride.

You’ll unclip from the pedals and then choose to calibrate:

Calibration takes a few seconds, after which it’ll come back with a success confirmation. If it fails, try giving the crank a few rotations, and attempt again.

With all that set, as you’re riding along you’ll see the data broadcast to your bike computer, based on which data fields you selected. When you pair a power meter for the first time to most bike computers, it’ll offer to add the most common power meter data fields. Here’s an example of some on my bike computer, coming from the Favero MX-2 pedals (with cadence and power coming from the pedals):

Another set, this time the cycling dynamics information, which now includes platform center offset, as well as seated/standing time and power phase.

Note that while the cycling dynamics metrics are now considered an industry-open standard, only Garmin has implemented it. Thus, you won’t see this data on a Wahoo bike computer (or Stages or Hammerhead or anything else). Favero was actually the first non-Garmin entity to add it, back a few years ago, but unfortunately, nobody else has followed along.

But other metrics like simple left/right power balance aren’t technically part of the cycling dynamics features, so most bike computers/watches support that. Likewise, cadence is also shown, and doesn’t require anything special – every bike computer on the market shows that.

From there, any other data is calculated on your bike computer (e.g. 10-second power is simply the bike computer calculating that). The same goes for things like normalized power, average cadence, total pedal strokes, etc…

Further, if you don’t have a Garmin head unit, you can at least see/show the cycling dynamics information on the Favero App as well:

Now, app aside, here’s the total bits displayed by the Favero Assioma Pro MX-2 MTB power meter:

– [ANT+/Bluetooth] Total power (combined left/right)
– [ANT+/Bluetooth] Power Balance (left/right split)
– [ANT+/Bluetooth] Cadence (RPM)
– [ANT+] Torque Effectiveness
– [ANT+] Pedal Smoothness
– [ANT+] Platform Center Offset (Cycling Dynamics)
– [ANT+] Seated/Standing Time (Cycling Dynamics)
– [ANT+] Power Phase (Cycling Dynamics)

Looking at the data recorded in a file, that too will vary based on your bike computer, but going with a Garmin unit, here’s what you’ll see at the general level, noting all the cycling dynamics bits listed (here’s an actual activity file to look at, recorded with the MX-2):

Then lower down, you’ll also see more cycling dynamics details with averages and such:

And finally, if you tap the Cycling Dynamics tab, you’ll see some pretty illustrations of data:

Next, moving onto something non-data, we’ve got battery charging. The unit uses a small set of clip-on chargers. These charging pods actually have micro-USB connections inside them, so while it comes with a very long dual-pronged cable, you could minimize the amount of stuff you’re bringing while traveling and just bring a smaller single micro-USB cable:

That said, as I commented to Favero, going with micro-USB for charging in 2024 seems a bit dated. USB-C should really be used here, which aligns to almost everything anyone else might travel with (e.g. a laptop/phone/etc charger). Of course, Favero noted it’s something they’re looking at, and certainly, they could offer a USB-C variant of that charging clip down the road pretty easily.

Favero claims 60 hours of charging time, and that seems quite viable. It’s always a bit challenging to track battery life, primarily in winter with vastly different conditions (some of my rides were with snow), which heavily impacts battery life. My general litmus test for something like this though is ensuring it’s not abnormally short, which didn’t happen here.

Finally, from a cleaning perspective, I haven’t had any issues with salt water (from beach riding) and then rinsing it off later.

Nor any issues with spraying it down with a hose after a muddy ride:

With all the daily usage bit covers, let’s take a look at the accuracy in terms of power, cadence, and more

Accuracy Testing:

I’ve long said that if your power meter isn’t accurate, then there’s no point in spending money on one. Strava can give you estimated power that’s ‘close enough’ for free, so if you’re gonna spend money on something it shouldn’t be a random number generator. Yet there are certain scenarios/products where a power meter may be less accurate than others, or perhaps it’s got known edge cases that don’t work. Neither product type is bad – but you just need to know what those use/edge cases are and whether it fits your budget or requirements.

As always, I set out to determine whether this unit is accurate and precise. In power meters today, one of the biggest challenges is outdoor conditions. Generally speaking, indoor conditions are pretty easy to handle, but I still start there nonetheless. It allows me to dig into areas like low and high cadence, as well as just how clean numbers are at steady-state power outputs. Whereas outdoors allows me to look into water ingest concerns, temperature and humidity variations, and the all-important road surface aspects (e.g. vibrations). For reference, the Favero Assioma Pro MX-2 unit has a claimed accuracy rate of +/- 1.0%.

For this testing, I’m mostly going to look at two different bike’s worth of data:

Road Bike (with some occasional gravel/offroad), equipped with:

– Favero Assioma Pro MX-2 (dual-sided)
– 4iiii Precision 3+ Pro (dual-sided)
– Wahoo KICKR CORE smart trainer (when indoors)

Mountain Bike, equipped with:

– Favero Assioma Pro MX-2 (dual-sided power meter)
– 4iiii Precision Pro (dual-sided power meter)
– Quarq XX1 MTB power meter
– Wahoo KICKR CORE smart trainer (when indoors)

I’m going to go through most of these relatively quickly, unless there’s a specific issue. You can click on any of the data sets to look at the underlying data yourself, if you’d like.

First up, let’s start with something simple – an indoor ride – an ERG workout in TrainerRoad. This one is actually on the Wahoo KICKR CORE smart trainer, and Favero Assioma Duo dual-sided pedals:

As you can see above, the green line of the KICKR CORE is settling down a bit during the warm-up, however, the two power meters (4iiii & Favero) are like best buds here, virtually identical across the board.

If I look at the left/right power balance split of one section later in the workout, you can see they trend very closely to each other. On the 2nd interval shown below, when my left leg is a bit lower there, you can see it matches on both of them that way. This is one area we’ll keep coming back to in this review. With dual-sided power meters, it can be somewhat challenging to get a bunch of them to agree exactly every time (to other units), but we want them to be pretty darn close – as total power on these units is simply the left side + right sided added together.

Next, looking at cadence, again, we see the units are virtually identical – save the KICKR CORE’s estimated cadence being a bit slow in some cases, which is normal for smart trainers using estimated cadence.

And then lastly, when we look at the mean-max power graph, which is a great way to see accuracy and alignment over longer periods, we see the two power meters are near identical, with the KICKR CORE a bit higher due to that earlier warm-up phase where it was reading higher. Still, on the whole this is actually a very pretty chart.

Next, we’ve got another structured workout, some 30×30 tests, which is a good place to look at both trainer and power meter responsiveness. This is a quickie I do with all power meters and trainers, so I won’t spend too much time on it here. Nonetheless, here’s the data (note: the colors have changed here, sorry!):

As you can see, again, near identical. The singular exception to that though is the first moment of the first interval, which seemed to catch the Favero unit a bit off guard and got a bit excited. The other units didn’t report that level of excitement.

In any event, looking at the left-right splits on a few intervals, you can see again, Favero and 4iiii are virtually identical here, especially once power is applied. We see a hair-bit more separation at some of the lower levels while soft pedaling (e.g. 90w), which can be somewhat common for power meters.

Looking at the mean-max graph, we do see more separation here at the top-end, due to the excitement shown by the Favero unit early on. Again, unclear to me if that’s real-excitement or fake-excitement. I’d argue it wasn’t real, but it can be difficult to suss out those slight nuances.

Now, let’s move from a structured workout to a non-structured trainer workout. This time in SIM mode, or simulation mode, where it’s simulating the terrain gradient in Zwift:

I know, it’s kinda a mess – such is life (and real-world pedaling). So, let’s zoom in on a few sections, starting with that sprint towards the end there. Looking at that, we can see very good alignment between the three units. There’s really not much to complain about here:

And if I look at that exact same timeframe, but now the left/right power, you can see again, they’re virtually identical between the two units. We see the Favero hold onto the sprint about 1 second longer than the other units (both above/below), which contributes to the average from Favero being slightly higher. But that’s not likely to actually be a Favero problem, but rather the simple reality of 1-second intervals for transmission/reception/recording rates (a blend thereof), driving these data differences. Said differently: It’s not likely a real-world data usage issue, just a recording/comparison issue.

Here’s another sprint, where we see the Favero and 4iiii units separated quite nicely (in a good way) on the left/right side, with both of those respective sides aligned together:

We’ve then got a blah-boring cadence graph, with things basically perfect:

And also a blah-boring perfect mean-max graph. Frankly, you won’t get much more perfect than this, save a tiny bit of differences on the KICKR CORE:

So, let’s head outside, and start to toy with things a bit. Here we’ve got a relatively efficient road-ride, and looking at the overall plot, obviously, it’s a bit variable:

So, let’s zoom in a few sections. First up is this section here, which looks very close. Again, the reality of power meters is you’re going to see very slight differences of opinions, especially outdoors. But this is pretty darn close:

Here’s another section, again, with very slight differences here as we’re later in the ride:

And then if we look at the left/right split of that same section, it’s very very close – save a few seconds here or there we see slight disagreements. But it’s nearly impossible to know in this scenario which one is ‘most’ right. And as we can see above, practically speaking it’s just not mattering – the total power is so close between them.

If I look at cadence, all seems identical there. There are two brief moments where cadence drops out for about 3 seconds on the Edge 1040 recording the 4iiii unit. However, this wasn’t just cadence dropping out, but all sensor data. I had a backup recording of the 4iiii on the Apple Watch (via Bluetooth), and I didn’t see the drop-out there. Thus it’s unclear to me if that’s an Edge 1040 thing, or a 4iiii ANT+ thing that happened.

And finally, the mean-max for that ride:

Next up, another outdoor ride, this one with some cobbled sections, some off-road sections, lots of road sections, and some sections I spent trying to figure out where TF the road went to. Here’s the data:

Now, I want to focus in on a few things with a bit more pickiness. Here’s a zoomed in section that’s virtually identical, for a half-hearted sprint. You can see there’s some slight disagreement on the ramp itself, but they basically get to the same spot.

And if you look at the left/right power split there, you see the two actually disagree about how I got there. The 4iiii says I had more left power, whereas the Favero says I had more right power. In total, both agree, but individually, they disagree on the composite of that.

Likewise, this section here. These two units are very similar, albeit the Favero is edging just slightly higher in some spots. Not a ton higher, but just barely higher at higher wattages. Or, one could say the 4iiii is edging barely lower in some higher-wattage spots.

You can see again that these two disagree on how that composite should be, but agree on that main sprint (point highlighted above), that the total power is the same but the left/right balances are quite a bit different for that exact second in time. Welcome to power meter analysis!

In some ways, going down the above rabbit hole can be never-ending.

However, where it comes concerning is when a pattern develops between differences in total power. And there is a slight pattern here on some rides (but not all rides), where the Favero unit is a bit higher than the 4iiii unit:

And if we look at the breakouts there, we notice the 4iiii is reading slightly lower, primarily on the right side, than the Favero pedals. Again, this doesn’t happen often, but happens mainly on surges. Sometimes. But not every time.

Again, I can go multiple rides in a row where this doesn’t happen, but then you find a ride where it does happen – and I don’t really have a great reason for it. For my riding and power output, it doesn’t seem to be a major concern, and seems to be fairly minimal, but it does have a slight effect on higher wattages for your total power curve. You can see that here. If I look at the mean-max point for the 10-minute  section, the two units are only a couple watts apart (totally normal). But as we climb higher and higher, they diverge more.

Next, let’s look at some dedicated mountain-bike testing. Because, we didn’t have enough data sets already somehow.

First up we’ve got a MTB set in chilly snow-laden weather. This starts off in the woods doing time there, before eventually heading out along the beach with salt spray (and when I say ‘spray’ that includes outright immersion at times). Here’s a look at that set at a high level, note, that this 4iiiii power meter below is actually a very different one than the previous one above. It’s one I bought a few years ago for my MTB, and is specifically designed for that.

Note that many years of comparing power meters in MTB conditions has demonstrated just how much different companies tweak algorithms to deal with all the terrain-induced impacts and craziness. Thus, I wouldn’t heavily overthink minor wattage differences on surges and such. Companies have varying amounts of smoothing to reduce errors, and some have more and other less.

Instead, it’s best to look at various points along the ride and ensure the multiple units are at least consistent, such as this snippet here:

Yes, there are differences there. But on the whole, they are more the same than different. In general, it seems that favero seems to smooth a tiny bit more than 4iiii, but on the whole they are very close, with a few moments they aren’t. I actually had a Quarq XX1 MTB unit on here, but it needed a manual calibration that I’d do later (due to changing chainrings, thus, I’ve remove it from the above set, because it wouldn’t have been a useful comparison).

Anyways, below again you can see how the units varied a bit, but were generally quite close.

Here’s a look at the mean-max data for that ride. While this isn’t as crispy as the road data, I’m actually pretty darn happy with it, given the variabilities in MTB:

To demonstrate the differences between road and off-road on the same ride, here’s a set where I started off on-road, then went off-road, and kept going back and forth on a circuit. In this case, I brought the now-happy Quarq XX1 unit along for the ride, thus having three power meters:

Looking at a few random points, here’s one here that’s very close, with the only disagreements being on the peak-power sprints (which were off-road sprints:

And again, very similar here on this off-road sprint, followed by other surges.

And finally, the mean-max power chart between the two. Most of the differences here come from the off-road sections, and how each company handles power smoothing/surges on rougher terrain.

All in, looking at far more data sets than I should have by this point, the units seem very good across the board. I don’t see anything of concern across any terrain types I’ve tested, with the terrain I have available to me.

Of course, this isn’t a surprise, given that Favero has always had leading-level accuracy, and many people have been using their first-get units off-road for years (in an unsupported buy functional config), so Favero has undoubtedly been using that timeframe to work out any kinks/etc….

And, that investment in time and validation seems to have paid off.

(Note: All of the charts in these accuracy portions were created using the DCR Analyzer tool. It allows you to compare power meters/trainers, heart rate, cadence, speed/pace, running power, GPS tracks and plenty more. You can use it as well for your own gadget comparisons, more details here.)

Power Meter Pedal Comparison:

I’m going to do another power meter pedal comparison video/post in the very near future. But, I typically don’t like doing these massive incredibly detailed comparison posts/videos only to have them voided a week or two later. As such, I’ll wait a week or two…because.

For funnies, here’s some quick comparison photos. Note, I wouldn’t judge the state of the Garmin Rally XC200 too harshly. It’s got about 20 months of riding under its belt, including most notably a lot of ocean beach and salt-water time. Seriously…lots of salt water. I try as best as possible to keep it clean, but…ice cream happens instead sometimes.

As you can see, certainly some visible differences. However, at the end of the day, all three units are accurate power-wise, and all three units are quite durable. Battery life, price, and weight are really the biggest differences.

Wrap-Up:

Ultimately, Favero appears to have a winner on their hands here. The units are solidly accurate, and solidly built, along with easy and reasonably priced replacements of parts should you need it. It now transmits the exact same information at Garmin’s much more expensive Rally XC-200 pedals (also SPD), but without the $1,200 price tag.

About the only real downside is the battery is substantially less than Garmin’s coin-cell units, which get a claimed 120-150 hours (more than double Favero’s). As always though, it tends to be a bit of a personal preference if you want a rechargeable battery or a coin-cell battery for your power meter. There are pros and cons to each.

I see it highly likely that I’d buy and equip other mountain/gravel bikes in my fleet with these, simply because they work well and are more reasonably priced. Aspects like being lighter weight is just a bonus, but one that allows me to eat more cookies – always a win in my book.

Thanks for reading!