Pedal-Assist (PAS) Cadence Sensor
The part that tells your motor you're pedaling. A failed PAS sensor is a top cause of 'assist stopped working' — and it's a cheap, easy fix.
The PAS sensor detects pedal motion (cadence) or pedal force (torque) and tells the controller to deliver assist. The common disc-magnet cadence sensor is inexpensive and one of the first things to check when pedal-assist quits but the throttle still works.
Replacement is straightforward: match the connector to your controller, mount the disc on the bottom bracket spindle, and align the pickup. Torque sensors are a higher-end upgrade for natural, proportional assist, but most conversions use the simple, reliable cadence type.
Where to buy
Two paths — match your spend to the build. Quality picks last longer and come with real support; affordable picks get you rolling for less. Always confirm fitment, voltage, and connectors for your bike first.
Quality picks
Pro tips from our test team
- Check the PAS sensor first when assist dies but the throttle still works.
- More magnet poles (12+) gives smoother, quicker PAS engagement.
- Match the connector to your controller before ordering.