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Favero Assioma Duo power pedals review

25 Jul 2018
Verdict:

Easy install and does exactly what it says on the box at a competitive price

Cyclist Rating: 
For 
• Easy install • Good for multiple bike owners • Accurate/consistent • Unobtrusive looks • Light
Against 
• Still a significant outlay • Must ride Look Keo pedal system

Like Keith Bontrager’s famous wheels axiom, ‘Strong, light, cheap… pick two,’ power meters have routinely failed to amalgamate the pillars ‘user-friendly’, ‘accurate’ and ‘affordable.’ But all that might be history…

Affordable

At two pints of lager and a packet crisps under £700, it’s tough to call the Favero Assioma power pedals cheap, but they are good value compared to the latest from the competition, and after several months of testing, I’m convinced they are the best stab yet at the Holy Trinity.

There’s stress on latest, because yes, older PowerTap, Garmin and Stages meters, to name but three, can be had for somewhat less.

Buy the Favero Assioma Duo power pedals from Sigma Sports here

But pitted head-to-head against the dual-sided competition (power meters that independently measure left and right leg power, as per the Assiomas), the recommended-retail leader board looks like this: Garmin Vector 3 pedals, £849; Quarq DFour91 crankset, £879; Stages Ultegra chainset, £949; PowerTap P1 pedals £1,050; Verve InfoCrank crankset, £1,050; Rotor 2INpower crankset £1,149; 4iiii Podiiiium Dura Ace 9100 crankset, £1,200; Shimano Dura-Ace 9100 Power Meter chainset, £1,500; SRM Origin 30 chainset, £2,800.

That list isn’t exhaustive but it gives you a sense of what the big power hitters are pitching,and where the Assiomas sit on the shelves.

Accurate

If you read the literature and believe it, the unit accuracy across that board varies from. +/-1. to 2%.

If you believe the anecdotal and pro evidence, SRM sits at the sharpest end of the accuracy spectrum. Favero says the Assiomas perform at the same +/-1% accuracy as SRM, with arguably the Assiomas’ most direct competition, the Gamin Vector 3, claiming likewise.

In practice, it is very, very hard to verify – or dispute – these claims. A recent study on power meters published in the International Journal of Sports Medicine concluded that, ‘Current power meters used by elite and recreational cyclists vary considerably in their trueness; precision is generally high but differs between manufacturers.’

In the worst instance said the study, a rider might need to readjust results by +/-2.8%. What’s more, the same product’s accuracy could differ significantly from unit to unit, by up to 5%.

In light of this, and without lab-standard benchmark, I can’t tell you if the Assioma pedals are as accurate as Favero claims. But, there was no evidence during testing that they were in any concerning way inaccurate.

Stacked up against comparative data from a set of InfoCranks, again anecdotally a very accurate meter, and my historical data from Wattbikes, Garmin Vectors and PowerTap hubs, the Assiomos read as I’d expect.

Regular loops tackled in the usual manner produced results that neither flattered nor undermined what I’ve learnt to expect of my legs.

I used the pedals in some pretty extreme conditions as well, at the tale end of our protracted arctic winter to nearly 40 centigrade in the Arizona desert.

Freezing rain to arid sun, the Assiomas coped just fine, the strain gauge’s nemesis, temperature drift (where swings in temperature distort results) was no worry for the Assiomas.

Favero will tell you a major reason for accuracy is the pedals have in-built gyroscopes that allow angular velocity (a key variable in calculating power, essentially how fast your pedal/foot is moving about the centre of the crank) to be measured in real time, during each pedal stroke, not averaged over several strokes as with other manufacturers.

They call it ‘IAV’ or ‘Instantaneous Angular Velocity.’ It makes sense in theory. In practice an extra benefit is the pedals, says Favero, are accurate with oval chainrings (where leg speed varies more significantly during rotations).

Because the pedals measure left and right leg power independently (Favero do a single sided ‘Uno’ version for £429), the system can generate pedal torque curves for technique analysis.

The theory being this allows riders to ‘train’ a smoother, more efficient pedalling technique. It’s arguably the most recent big USP laid down in the power meter market, and is noting new.

But still it keeps the Assiomas bang up to date with the latest data any bike-based power meter can harvest.

User-friendly

Here is the main reason I would recommend the Assiomas – they are a pedal based meter, which makes installation on any bike, and swapping between bikes, an absolute cinch.

Regular 8mm hex wrench plus elbow grease = fine fitment. No need for torque wrenches it would seem, unlike say Garmin, which recommends precise torquing for the Vectors.

A 40Nm torque wrench won’t have many more applications in the usual cycling toolbox, and it ain’t cheap. Another equation: esoteric tools = annoying.

I was careful to use the supplied pedal washers since the strain gauge gubbins are housed in a ring around the axle, and for satisfactory operation it’s paramount this part mustn’t touch the crank arm.

Different cranks may or may not need them, and since the pedal axle is 54mm long, basically the same as any regular pedal, there are no Q-factor issues.

I swapped the Assiomas happily between several bikes and they made a journey across the Pond and back with no dramas.

Oddly the pedals do not have a manual sleep mode, so I had half expected them to arrive in Arizona with depleted batteries, as movement/vibrations sets them off, and they were in the hold. However, this proved not to be the case.

I asked Favero about this and they replied, ‘Assioma currently has an automatic system (basically based on the type and intensity of the detected movements) that prevents involuntary battery discharge during travel, but we are going to include also a "manual" option in the near future.’

That mode will eventually get added through a firmware update, of which there have been two major ones since testing these pedals, one to improve accuracy, the other to solve issues between the pedals and some head units, notably Wahoo.

It’s good to see that Favero is monitoring the real-world success of its product, but worth noting if you buy a set an update might be necessary depending on the batch they came from, and regular update checks are a good idea.

Those updates come via the Assioma app, which is essentially just an interface to do updates and check pedal battery life. There is as yet no number crunching in the app, rather all that gets done by third party software such as Strava or TrainingPeaks.

The pedal is made on the Look Keo platform, courtesy of pedal company Xpedo. It looks near identical, but the clip in/out feel is slightly tighter with a genuine Look cleat as opposed to the supplied Look-licensed cleat. No biggie, unless you ride Speedplay or
Shimano or Time.

Buy the Faveo Assioma Duo power pedals from Sigma Sports here

The party line is there is no need to re-calibrate/zero offset unless you swap the pedals between bikes. Some people will judiciously calibrate the pedals before every ride anyway, others won’t care to, and I fell into the latter camp and the pedals seemed happy enough.

But if belt and braces is your bag, calibrating is as easy as following a few steps on your paired head unit, and takes mere seconds and can be done out on the road.

Lastly, charging. The literature reckons on 50 hours ‘normal’ riding between charging, and I’d say that’s not too far off, if anything, a little conservative.

Charging is done through two proprietary magnetic USB chargers with good long cables meaning you can easily charge your the pedals in situ. Assioma also supplies a dual-USB socket plug. A nice touch.

Would you, should you?

Ultimately, the limit to Favero Assiomas is the software the data goes into and your understanding of it.

There’s nothing here that’s lacking in any way, they sample all the necessary data, do so accurately it would seem (or at least, consistently within themselves), and it’s down to third party software to extrapolate the numbers.

So add together the ease of installation and swapping between bikes, the build quality – which seems very good, the pedals themselves are sturdy and neat looking – and price, and the Favero Assiomas are as good a pedal-based power meter as currently exists.

Oh, and they are also the lightest, coming in at 149g per pedal versus 161g (Vector 3) and 216g
(PowerTap P1).

PowerTap does have replaceable AAA batteries, but (a) that is kind of annoying (b) it is very unlikely that with 500 charge cycles you’ll ever have battery issues with the Assioma pedals, or Vectors for that matter (plus after that point, the batteries don’t fail they just become slightly less efficient).

Simple, light, accurate, neat and kind of cheap. Pick five.

Price: 
£689

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