The cadence sensor or PAS (Pedal Assistance System) is a mandatory element in electric bikes in European countries. This sensor enables automatic activation of the motor assistance when pedaling.

The cadence sensor consists of two elements: 2 discs with magnets and 1 sensor with a holder.

It is compatible with the following bottom bracket standards:

• Octalink I,
• Octalink II,
• ISIS,
• with external bearings (Hollowtech cranks)
• Square

The sensor is mounted under the bottom bracket nut. A chainring with magnets is usually installed instead of the smallest sprocket in the crank.

Number of measurement points: 12 and 8

The distance between the sensor and the magnetic disc should be approximately 1-2 mm.