Favero Assioma Maintenance & Rebuild Guide: Bearing Service, Pedal Body Swaps & Genuine Spares

Among high-performance cycling power meters, the Favero Assioma platform stands out for an engineering philosophy that is increasingly rare in modern cycling: complete mechanical modularity and long-term rider serviceability. While competitor systems often force riders to ship pedals across continents for simple bearing replacement or declare an entire unit totaled after a criterium crash, Favero isolates all delicate piezoelectric strain gauges and electronics permanently inside the hardened steel spindle and sealed resin casing.

Because the strain sensors and rechargeable lithium batteries are hermetically sealed at the factory in Italy, you can completely overhaul the cartridge bearings, swap damaged outer pedal shells, or refresh seals without disturbing factory calibration or altering power accuracy.

However, precision hardware requires precision maintenance. Installing bearings incorrectly, using the wrong socket clearance, or misinterpreting thread directions can damage the pedal spindle or cause bearing binding. This guide outlines the exact factory specifications, directional thread rules, torque values, and genuine spare parts required to keep your Assioma DUO, UNO, and PRO pedals spinning smoothly for tens of thousands of miles.

1. Diagnosing Bearing Wear vs. Normal Free-Spinning

Riders new to Favero Assioma pedals are frequently surprised by how freely the pedal body spins compared to sealed Shimano or Look road pedals. Unlike standard pedals packed with heavy viscous grease and tight contact seals designed to stay stationary when you clip out, Assioma pedals utilize high-precision micro-cartridge bearings engineered for minimum frictional drag. A pedal body that spins for several revolutions when flicked with a finger is completely normal and healthy.

Bearing service is indicated when you detect either of two mechanical symptoms:

• Lateral (Axial) Play: Grasp the crank arm firmly with one hand and wiggle the outer edge of the pedal body laterally (inboard and outboard along the spindle axis). Any detectable click, knock, or rocking motion indicates bearing race wear or loosening of the internal M6 retention locknut.
• Roughness or Grittiness: Slowly rotate the pedal body by hand while gently pressing inward toward the crank. If the rotation feels indexed, notch-like, or gritty, road grit has bypassed the outer seals and compromised the steel ball tracks.

2. Step-by-Step Bearing Overhaul (DUO & UNO)

Servicing the bearings takes approximately 15 to 20 minutes per pedal. Work over a clean magnetic parts tray so small washers and seals cannot roll away.

1. Remove Pedals from the Bike: Place an 8 mm hex wrench into the back of the spindle axle. Use the mechanic's golden rule: rotate toward the rear of the bike to loosen both pedals (Left pedal unscrews clockwise; Right pedal unscrews counter-clockwise).
2. Extract Outer Dust Cap: Using a flat coin tool or wide flat-blade screwdriver, unscrew the plastic end cap by turning counter-clockwise. Inspect the cap's tiny O-ring for tears.
3. Remove the Internal M6 Locknut: Secure the spindle axle with your 8 mm hex wrench from the back. Insert your thin-walled 9 mm pipe socket (CH9) into the outer body recess.
   CRITICAL: On the Left pedal, unscrew counter-clockwise (standard thread). On the Right pedal, unscrew clockwise (reverse thread). Remove the M6 nut and the underlying brass washer.
4. Slide Body Off Spindle: Gently slide the outer pedal body off the spindle axle. Note the arrangement of the internal components: inner oil seal, inner cartridge bearing, and outer dual cartridge bearings. Wipe the polished stainless steel spindle shaft clean with a lint-free microfiber cloth.
5. Press Out Old Bearings: Using a blunt brass punch or bearing drift, press the three micro-cartridge bearings out of the pedal body shell. Clean the inner bearing seat surfaces thoroughly with isopropyl alcohol.
6. Install Fresh Bearings & Oil Seal: Using the genuine Favero Bearing Service Kit (Art. 772-72), gently press the new cartridge bearings into the pedal shell, pressing strictly on the outer bearing race (never press the inner race, which ruins the ball tracks). Press the fresh oil seal into the inboard recess.
7. Grease & Reassemble: Apply a light, uniform coat of high-grade synthetic lithium grease to the spindle shaft. Do NOT get grease on the resin sensor pod or the gold magnetic charging contacts! Slide the pedal body onto the spindle, install the washer, and thread the M6 locknut.
8. Torque Locknut & End Cap: Torque the internal M6 locknut to 8–10 N·m using your calibrated torque wrench. Spin the pedal: it should rotate smoothly without friction or lateral wiggle. Thread the outer dust cap clockwise and tighten strictly to 2–3 N·m (hand-snug).

3. Crash Replacement & Pedal Body Swaps

One of the most stressful moments in road racing or gravel riding is a high-speed crash where the pedal strikes tarmac or rocks. With integrated power meters like Garmin Rally or SRM, a heavily abraded pedal body can lead to costly factory repairs.

With the Favero Assioma architecture, the outer pedal body is simply a sacrificial composite or aluminum shell. If you break a spring clip, crack a retention jaw, or grind down a corner during a crash, you do not need to replace the $499+ power meter. You only need a replacement pedal body:

4. The Magnetic Charging Ecosystem: Micro-USB vs. USB-C

One of the most frequent customer inquiries we receive involves charging connector compatibility. Because Favero has innovated across generations, there are two distinct magnetic charging standards in circulation:

• Legacy DUO, UNO & DUO-Shi (Micro-USB Standard): The original Assioma family features the distinctive cylindrical resin sensor pod clamped next to the crank arm. Charging terminals are two gold pins located directly on the resin pod exterior. They use the Micro-USB Magnetic Connector Set (Art. 773-00-61), which snaps onto the pod and accepts standard micro-USB charging cables.
• Assioma PRO RS & PRO MX (USB-C Standard): The newer Assioma PRO series moves all electronics inside the spindle itself. Charging terminals are magnetic concentric rings positioned at the very tip of the outer spindle axle. They use the USB-C Magnetic Connector Set (Art. 773-00-67), which accepts standard modern USB Type-C cables.

5. Cleat Selection & Biomechanical Float Tuning

The final critical component of your Favero power system is the cleat interface. While standard Look Keo pedals accept generic third-party cleats, Favero Assioma power meters achieve optimal zero-offset stability and noise-free power transfer when paired with genuine factory cleats:

Official Favero Look Keo Cleats feature co-molded, high-friction polytetrafluoroethylene (PTFE) contact pads engineered to match the tension spring rate of the Assioma retention jaw. This prevents the high-frequency creaking and micro-rocking common with hard plastic imitation cleats.

For a deep engineering dive comparing float kinematics, platform width, and foot stability between three-bolt road pedal platforms, explore our companion analysis: Shimano SPD-SL vs. LOOK Keo: Technical & Power Meter Guide.