Precise and accurate power meter with rechargeable batteries that’s Shimano-friendly.
accurate and reliable power measurement;
set-it-forget-it ease of use;
BYO pedal bodies add cost;
q-factor may not be for everyone;
travel mode requires charging cable to wake;
The reliability of these power meter pedals is excellent, and the ease of swapping between bikes makes them an great choice for those with more than a single road bike.
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For years, those who wanted power meter pedals had few options other than using Look Keo cleat compatible pedals. Italian manufacturer Favero debuted the Assioma Duo Shi (dual-sided Shimano) power meter some four years after the debut of its Look-compatible version, in 2017. Unlike the Look compatible version of the power meter, which arrives as complete pedals with power meter spindles and pedal bodies ($733/set), the Shimano version is sold as power-measuring spindles-only, so you’ll have to bring your own pedal bodies, or make an additional purchase.
Also read: Favero Assioma power meter review
The Favero Assioma Duo Shi is compatible with Ultegra R8000, R6800, R7000, R550, and R540 three-bolt road pedals. Owners of Dura-Ace pedals will need to swap to different pedal bodies if they want to use the Assioma power meter, as the pedal bearings in Dura-Ace pedals are different from other Shimano road pedals, and not compatible with the Favero bearing configuration. Making just the power measurement “guts” available to consumers reduces the cost, and allows owners of most Shimano road pedals to upgrade their pedals without having to buy extraneous hardware. Unlike Garmin and SRM, Favero is not currently producing a pedal that is compatible with two-bolt cleats, or off-road pedal systems.
Size, weight, fit
The Assioma Duo Shi power meter electronics are entirely housed in the spindles, which weigh 99g each. Complete pedal weight varies depending on the version of the pedal body that is used; Ultegra R8000 pedal bodies with the Assioma spindles tilt the scales to 156g per pedal.
For comparison, a set of Favero Assioma Look pedals are 305g per set, so the fully assembled Assioma-Ulegra pedal is pretty close in weight. Pedal stack height is also dependent on the model of the pedal body and is in no way affected by the Favero electronics.
Riders who are sensitive to q-factor — the distance between the outside of the crank arm and the center of the pedal platform — may have to adjust to using the Assioma Duo Shi.
Compared with the standard Ultegra pedal without a power meter (53mm), the Assioma Duo Shi pedals have a q-factor that measures 64mm on each side. For reference, the Garmin Vector 3 and the latest Rally power meter pedals have a q-factor of 53mm. I never noticed this difference when swapping between bikes with the Assioma Duo Shi pedals, or when riding a different bike with different pedals on it. And, some riders who experience knee pain may even want a fit with a greater q-factor.
Battery and electronics
Like the Look version of the Assioma, the Shi version of this power meter has a pod at the base of each spindle that houses a rechargeable battery, and the ANT+ and BTLE antennas. LEDs on the pods display charging status, and also when the pedals are ready to connect to a bike computer for a ride. The batteries are charged with a set of two-meter-long cables that have proprietary-shaped magnetic clips that connect to the pedals and keep the harness in place during charging. These clips and cables are the same as the Look version of the power meter.
Note: this harness is required to wake the pedals from travel mode, so if you put the pedals into a deep sleep for travel (this mode is different from the sleep mode when the pedals are not in use), make sure you bring the charging harness along, to wake the pedals.
Favero claims about 50 hours of battery life between charges, and with a full charge, I am able to get 43 hours of riding before being presented with a low-battery message on my Garmin Edge 530. The Favero app displayed a yellow battery status indicator that suggested there is about 15 percent of the battery capacity remaining (there is no numerical value presented, just a horizontal, color-coded status indicator) when the message to recharge the pedals is displayed.
Installation and configuration
Swapping out the stock Shimano Ultegra R8000 road pedal spindles for the Assioma power meter spindles is really, really easy — even for those who are not mechanically inclined — and takes fewer than five minutes.
Favero includes instructions with the set of spindles, and the most important thing to remember is: Just like the threads that mount the spindle into a crank arm, the right pedal spindle threads are reversed (this is captured in the included Favero assembly and installation diagram). I use a 17mm cone wrench to remove the stock spindles, and a 19mm cone wrench to install the Favero spindles. If your toolbox does not include these two different wrenches, a small adjustable wrench with thin jaws works, too.
The Favero Assioma Duo Shi ships with an 8mm hex wrench that makes mounting them onto crank arms a quick and easy task. Once the pedals are installed on a crank, the Favero mobile app is required to register the pedals with Favero — they will not work without the step — as well as to zero the power meter after installation, like when moving them between bikes. There are other settings in the Favero mobile app for crank length, time elapsed before pedals go into sleep mode, and more.
You can read more about them in my review of the Favero Assioma Look version.
Once zeroed, Favero claims no the only time the pedals will need to be re-zeroed is when reinstalling them, like when swapping between bikes. While not necessary, I still go through the calibration routine with my Garmin Edge 530, which is easily paired to the pedals, prior to each ride. The Favero electronics also pair easily with a Garmin Fenix 6 watch, a Wahoo Elemnt Bolt, and also with my Mac PowerBook Pro for use in Zwift.
Use and performance
The Favero Assioma Duo Shi is really easy to use and provides consistent, accurate, and reliable power measurement. The electronic “guts” are robust and hold up to riding in the rain as well as temperature changes during rides. Comparing the Assioma Duo Shi to Wahoo Kickr Core, and a Stages L Ultegra crank arm, I thought the measurements are trustworthy, and reliable even when riding with them in a non-clinical environment – outdoors, on the road. Favero claims the accuracy of the Assioma to be within +/- one percent.
Data sent by the Assioma pedals are displayed the same way as data from any power measurement source.
When using Garmin Connect to record and track rides, the only data field that is not imported is the Platform Center Offset (PCO), which indicates the left/right offset from the pedal body centerline in millimeters for each of my cleats. This is certainly not a deal-breaker; the only time I really care about this metric is after installing new cleats on my shoes, and also coming back from injury, and wanting to see if my pedaling is balanced or not.
At half the cost of the Gamin Rally pedals, and $300 less than the Wahoo Powrlink Speedplay compatible pedals. This of course acknowledges that pedal bodies are not included and may be an additional $99-$199 purchase for those who do not already own compatible pedals. I really like the rechargeable battery feature of the Assioma: there is no waste headed for a landfill, nor issues with batteries rattling around in a battery compartment when riding on less than perfectly-smooth roads. The data provided by the Favero pedals is accurate and reliable, and I think this is the most important factor when evaluating a power meter. I trust the data, and let it inform my riding, without questioning it. The Favero Assioma Duo Shi power meter is a great value and provides reliable, actionable, and trustworthy information