Sprag Bearing inside the Belt Pulley for Brose Motors

Sprag bearing for Brose Motors:

Sprag clutch bearing, used in the drive pulley of Brose Alu S and Brose Mag S motors.

The sprag/clutch bearing is a critical component of the internal drive train of Brose Alu S and Mag S motors. Its function is to act as a one-way clutch integrated into the pulley, allowing torque transmission in one direction and disengagement in the opposite direction. This ensures smooth power delivery, reduces pedal backlash and protects the internal gears from reverse loads.

The word sprag describes the form of the teeth that grip the shaft.

The precision of the bearing and the quality of the sprag system are essential to prevent noise, slippage and ensure the efficiency of the motor.

At BiciFix we no longer sell the metal cage version of this bearing which was popular in the last few years. While completely apt for the service of the motors, these bearings sometime have tolerances leading to higher friction. We are now stocking only the reinforced version of the original bearing, available from the original manufacturer of the bearings:

Reinforced plastic cage sprag bearing – Reinforced bearings from the original manufacturer of the original bearings in Brose motors – RINGSPANN. They come with a better finish and dimensions. Origin: Germany.

Important technical note from BiciFix

To replace this bearing, it is necessary to first remove the large bearing from the pulley and heat the pulley in order to remove it and install the new clutch correctly.

Compatible with all Brose motors – aluminum Brose motors Gen 1 and Brose S Brose Gen 2 – magnesium motors – Brose S Mag

Technical Specifications