E-bike motor clicking or grinding? Causes and repair instead of replacement
Does the motor click under load or grind in a way you can feel in the pedals? Then a systematic check is worthwhile before you think about a new motor. Bearing damage can be behind such noises, but so can a part outside the motor.
Rule out first: parts outside the motor
Clicking noises also arise at the pedals, crank bolts, chainring bolts and the chain. Check these points first. No special tools are needed for this.
Possible cause inside the motor: the crankshaft bearings
If water gets past the seals, it can wash the grease out of the bearings. The bearing corrodes and develops play. Bosch, Shimano, Brose and Yamaha therefore prohibit cleaning the drive with a pressure washer in their manuals.
How to check a crankshaft bearing
- Check for play: Grip both crank arms and shake them sideways. Noticeable play indicates a worn bearing.
- Narrow down the noise: Note whether the noise only occurs when pedalling under load or also when pushing the bike. This helps the workshop with the diagnosis.
- Rattling on descents: On the 4th-generation Bosch Performance Line CX, rattling on rough descents is a known phenomenon; Bosch attributes it to vibrations of the drivetrain. More on this in our guide Bosch CX rattles: normal or a defect?
Repair instead of replace?
Bearing damage does not automatically mean a new motor. Bearing sets and service kits are available for many drives, for example for Bosch, Yamaha and Shimano STEPS. Fitting them, however, requires opening the motor. Bosch states in its manuals that the drive unit may only be opened by qualified specialist personnel and that unauthorised opening voids the warranty claim. As long as the statutory warranty or a guarantee applies, the specialist dealer is therefore the first port of call. Our guide How much does an e-bike motor repair cost? shows what a repair costs compared with a replacement motor.
Bearings and bearing sets for each drive (prices at bikely as of 10 October 2026):
- Bosch Classic Line DU25 / DU45: crankshaft bearing €24.95
- Bosch 2nd generation (BDU2xx): crankshaft bearing €24.95, repair kit with main bearing and crankshaft bearing (CX/Speed) €59.95
- Bosch 3rd generation: crankshaft bearing €24.95
- Bosch 4th generation: crankshaft bearing €24.95, service kit €159.95
- Yamaha PW, PW-SE, PW-ST, PW-TE: crankshaft bearing left €19.95 and right €29.95
- Yamaha PW-X / PW-X2: bearing set ENDURO €64.95
- Shimano: overhaul kit for EP8 €99.95 and for E8000 €89.95
Matching parts: Bearing sets and service kits · Crankshaft bearings · Greases
Sources: Bosch manual (cleaning) · Shimano manual E8000 · Brose manual · Yamaha manual PW-S2 · Bosch drive unit manual (opening, warranty). As of: October 2026.
