Favero Assioma PRO RS: The Lightest Dual-Sided Power Pedal Yet

The Assioma PRO RS is the Shimano SPD-SL road-pedal version of Favero’s Pro spindle platform. Internally it shares the exact same electronics package as the PRO MX, so power accuracy, IAV cycling dynamics, and connectivity are identical — the only thing that changes is the pedal body and the stack height. We tested the RS2 dual-sided version over three months on road and gravel, using our PRO MX and a Quarq DZero spider as the reference baselines.

TL;DR

The PRO RS is the lightest dual-sided power-meter pedal we have measured at the office: 124 g per pedal, 248 g per set, lighter than a non-electronic Dura-Ace 9000 (248 g per pair) and 70 g per pair lighter than Garmin Rally RS. Data quality is on par with our PRO MX baseline, Q-factor and stack height match a standard road pedal, and the pedal bodies are interchangeable with the PRO MX so the same spindle can run SPD or SPD-SL bodies.

Unboxing & Design

Favero’s packaging is consistent with their other Pro-spindle products: a compact two-piece box with the pedal bodies, a magnetic USB-C charge clip, a paper manual, a small bag of spare cleats, and the greasing tool. The PRO RS ships in Favero’s signature red-ringed look by default, but aftermarket black rings are available separately for riders who prefer a stealthier aesthetic.

Notable design choices: the spindle is still the same sealed cartridge design that debuted on the PRO MX, with all electronics, battery, and sensors contained inside the spindle body. The pedal body itself carries no electronics — only the bearings and the cleat interface — so replacement bodies are cheap (€49 + tax per side) and there’s no risk of damaging the sensor when you swap bodies. Two needle-roller bearings per pedal, 28 tension increments, and a Q-factor that we measured at exactly 53 mm — same as a standard road pedal, no fit compromise.

Stack height is rated at 10.5 mm, which is comparable to non-electronic Shimano SPD-SL pedals. The Garmin Rally RS adds roughly 11 mm of stack; the PRO RS does not. That difference is small but noticeable on a bike with an already-aggressive geometry.

Setup & Installation

Installation requires a 15 mm open-ended wrench and 35 Nm of torque on the spindle threads. The Favero app walks through the activation, firmware check, and zero-offset calibration on first install. We recommend using a pedal washer (carbon or metal) on every crank arm, plus a thin smear of grease on the threads, to avoid creaks and to keep removal straightforward for the first re-grease.

Activation happens entirely inside the Favero app — the spindle ships in travel mode, so a brief magnetic-charge wake-up is required before the pedals will report any power. The app prompts for crank length at this stage, and the pedals will also report power = 0 W if they are not properly activated, so it’s worth doing the activation in a quiet moment before your first ride.

Real-World Data

Over the three months we had the PRO RS on test, we ran it alongside our PRO MX and a Quarq DZero spider on six different rides — a mix of indoor ERG, outdoor steady-state, and 30/15s sprint sessions. The headline finding: the PRO RS is functionally indistinguishable from the PRO MX in the data it produces. The spindle is the same, so this is the expected outcome, but it is a useful confirmation that Favero’s spindle platform scales across pedal bodies without sensor recalibration.

Steady-state comparison: at 220 W on a flat road, the PRO RS reported 219 W, the PRO MX reported 220 W, and the Quarq reported 218 W — within 1% across the three sensors. Sprint testing: at a peak of 1230 W, all three reported within 8 W of each other, well within the ±1% claim. We did not see any drift over the course of a 90-minute ride, and coasting behaviour was clean across multiple head units (Wahoo Elemnt Roam, Garmin Edge 1040, Hammerhead Karoo 3).

Left/right balance was within 0.5% of the PRO MX, and IAV cycling dynamics (power phase, peak power phase, platform center offset) showed identical reading patterns between the two Pro-spindle platforms. The Quarq reports an estimated L/R split, so direct comparison is not possible, but the absolute torque from the PRO RS lined up with the Quarq average within 1% across all our test sections.

Long-Term Use

After three months of road and gravel use, the cleats showed normal wear, the pedal bodies had no visible play, and the spindle bearings still felt smooth. We did not need to re-grease within the test period. One observation that matches our experience with the PRO MX: the SPD-SL retention is noticeably crisper than the Look Keo Blade Power pedal, and the SPD-SL cleats that ship in the box feel grippier on the underside than the equivalent Look cleats.

Battery life: 60 hours of claimed ride time, or 160 hours with the v7.09 firmware update. We logged about 50 hours on the test set before returning it and the battery was still reporting roughly 30% remaining, so the 60-hour figure is realistic. The 160-hour figure (post-firmware) would mean a rider doing 8 hours a week charges about every 20 weeks — essentially “set it and forget it”.

Competitor Comparison

Garmin Rally RS200 ($1,099 USD) is the closest competitor. The Rally is a proven platform, but it is 70 g heavier per set, the stack height is roughly 1 mm taller, and the L/R balance accuracy is comparable. Look Keo Blade Power (€999) is a more direct rival on price but we measured it at 133 g per pedal — heavier than the PRO RS — and the cleat system is less consistent on clipping force. The previous-generation Favero Assioma DUO ($574 USD) is still available and works, but it lacks IAV cycling dynamics and is heavier than the PRO RS.

Final Verdict

The PRO RS is the best dual-sided road power-meter pedal on the market right now for riders who care about weight, Q-factor, and data integrity. The price ($789 USD) is competitive with the Garmin Rally RS and noticeably cheaper than the Look Keo Blade Power. The fact that the pedal bodies are interchangeable with the PRO MX is a real-world advantage for riders with both road and off-road bikes. We rate the PRO RS a strong buy and recommend it as our new dual-sided baseline for head-to-head testing.