Favero Assioma DUO-Shi puts power meters inside your Shimano SPD-SL road pedals

Tips & Reviews

Two years ago we turned up the Favero Assioma, the lightest power meter pedals you’ve never heard of, but now they are back with a new set of DUO-Shi spindles that slide power measurement into your existing Shimano road pedal bodies. Why is that better than their original Look-compatible version? And what are the downsides? Let me explain…

Favero Assioma DUO-Shi makes Shimano road pedals power meters

Favero Assioma power meter pedals, lightest two-sided left/right low maintenance pedal-based powermeter

Favero’s Assioma power meter pedals are simple in concept. With the strain gauges inside a special set of spindles and the electronics for power, processing & communication inside a compact housing around the stainless steel axle next to your crank arm, they are compact & self-contained. That means a lightweight, conventional road pedal body that works with regular road cleats (& road shoes), and all the sensitive gadget bits are safely out of the way of regular road impacts & possible crash damage.

And as with most pedal-based power meters, they are quick & easy to move from one bike to the next.

Favero Assioma power meter pedals, lightest two-sided left/right low maintenance pedal-based powermeter

The fact that the Look-compatible Assioma pedals deliver top-tier ±1% power accuracy at just 150g per pedal, low 10.5mm stack, low 54mm pedal Q-factor, at just 690€ for true dual-sided power measurement is hard to argue with.


A lot of road cyclists are super picky about their pedals. And many prefer the wider pedal platform support of Shimano SPD-SL pedals, even their improved walkability. So Favero has been developing a Shimano-compatible Assioma DUO system for quite some time. And now it’s ready.

What’s new in DUO-Shi? And why?

Favero Assioma DUO-Shi Shimano SPD-SL compatible road power meter pedal spindle kit, render

Basically, Favero reworked their Assioma power metering spindle to fit inside the regular Shimano pedal bodies that you are already riding. It’s actually cheaper than their Look DUO setup, and you can upgrade Shimano SPD-SL pedals from Tiagra all the way up to Ultegra with the same DUO-Shi setup.

The catch?

Your pedal stance is going to get a lot wider – your feet are going to end up around 2cm farther apart…

Wider pedal Q-factor

Favero Assioma DUO-Shi Shimano SPD-SL compatible road power meter pedal spindle kit, Q-facto & stack heightr

The 64-65mm DUO-Shi pedal Q-factor (add that to crank arm Q-factor to see how wide your feet will be from the centerline of the bike) adds 12.8mm to each side over the standard 52mm Q-factor Ultegra pedal, or 8.8mm extra if you have Shimano’s extended axle ergonomic 56mm Q pedal spindles. Double that to see how much further apart your feet will be.

Now is that a problem?

Many road cyclists have found ergonomic improvement from going to wider pedals to balance wider thighs or hips, but that won’t be everybody. Most road pedals are in that 52-56mm Q of Ultegra pedals, but Speedplay were often praised for originally offering up to a 65mm Q-factor spindle.

And even some cyclists who ride more on mountain bikes (which generally have much wider cranks Q-factor to fit bigger tires) have favored increased Q on their road or gravel bikes for a similar ride. Then again, many (like myself) often jump from super-low road/gravel bike Q (52mm pedals on 145.5mm cranks) to much wider MTB trail bike Q (57mm pedals on 172mm cranks) without any issue – that’s more than 3cm per side!

Whether the extra Q-factor of the Assioma DUO-Shi power meter pedals will be a problem is going to be a personal decision. But Favero figures many riders will still benefit from the upgrade to power metering.

Tech details

Favero Assioma DUO-Shi Shimano SPD-SL compatible road power meter pedal spindle kit, angled

The bulk of the tech & spindle is the same as in the original Favero Assioma, inside a new adapter for the Shimano pedal body, although not interchangeable or able to be converted from the Look version.

That means you get the same ANT+ & BLE transmission of data with L/R balance, torque effectiveness, pedal smoothness, IAV Power Phase, and IAV Rider Position. The power meters are rated up to 3000W with +/-1% accuracy. They feature built-in cadence sensors, 50hr lithium batteries rechargeable with Favero’s USB dongle.

What is different is that the Assioma DUO-Shi uses a tiny sealed bearing at the outside (like the original Assioma), but a low-friction glide bushing on the inside due to space constraints in the Shimano bodies.

Each sensor spindle weighs 99g without a pedal body, meaning a claimed weight of 157g per pedal with an Ultegra R8000 pedal body installed (just over 33g more than Shimano’s claimed weight per pedal.)

How To get dual-sided power metering from Shimano pedals?

OK, so now that we understand the tech inside (and you are fine with the added Q-factor), you still can only buy the spindles themselves. You still have to install them into your existing Shimano SPD-SL pedal bodies yourself. It’s not such a difficult process, and Favero had the step-by-step instructions to get you there.

Favero Assioma DUO-Shi power meters – Pricing & compatibility

Favero Assioma DUO-Shi Shimano SPD-SL compatible road power meter pedal spindle kit

The single Favero Assioma DUO-Shi power meter pedal kit is compatible with all Ultegra R8000/R6800, 105 R7000, Tiagra R550/R540 SPD-SL pedals.

The made-in-Italy Assioma DUO-Shi kit sells for 690€ (including VAT), is IP67 rated waterproof, and includes a 2-year warranty. The new power meter pedal kit is available now, and ships within a week, so you’ll be swapping out your Shimano axles for power sensors in no time!


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