Shimano EP8: spotting bearing damage and replacing the bearings

If your Shimano EP8 makes new noises or the crank has play, a bearing inside the motor can be the cause. Only the opened motor shows this for certain. This guide helps you rule out other causes first and tells you what Shimano writes about opening the motor.

Rule out the simple causes first

Noises around the cranks do not have to come from the motor. So first check what you can reach from the outside. The torque values come from Shimano's dealer's manual for the EP800 series:

• Are both crank arms tight? Shimano specifies 12 to 14 Nm for the clamp bolts of the crank arms, tightened alternately and evenly. For the left crank, Shimano advises checking the torque after about 100 km and regularly after that.
• Is the lock ring of the chainring unit tight? It has a left-hand thread, and Shimano specifies 35 to 45 Nm.
• Are the pedals tight and do their bearings run smoothly?
• Is the chain clean, lubricated and not stretched? Shimano advises cleaning it regularly with a suitable chain cleaner.
• Are the bolts that hold the motor in the frame tight? Shimano specifies 10 to 12.5 Nm for the drive unit mounting bolts (M8). The bolts are supplied by the bicycle manufacturer.

Signs that can point to a bearing

• The crank can be rocked sideways to the axle although the crank arms are tight.
• A grinding noise has appeared that was not there before.
• There are traces of rust at the crank axle. Shimano names rust as a possible result of water getting in.

These are indications, not proof. Other parts in the motor can wear too, for example freewheels or seals. Which part is affected can only be seen once the motor is open.

What Shimano says about opening and care

In the dealer's manual for the EP800 series (DM-EP800-04), Shimano writes that the product must not be disassembled. For questions about installation and maintenance, Shimano refers to the place of purchase, and only genuine Shimano parts are to be used. If your bike is still covered by statutory warranty or a guarantee, talk to your dealer first before anyone opens the motor.

On care, the manual says: the components are designed for riding in wet weather, but should not be deliberately placed in water, and the bike should not be cleaned with a high-pressure washer. If water gets in, this can lead to operating problems or rust according to Shimano. According to the manual, natural wear is not covered by the guarantee.

Replacing the bearings: a job for a specialist workshop

The bearings sit inside the motor. To replace them, the motor has to be opened. That is a job for a workshop that overhauls e-bike motors. We sell the parts, we do not fit them.

For the Shimano EP8 (DU-EP800) we stock the overhaul kit PLS20701EP, suitable for Shimano EP8, €99.95 (price at bikely, as of 11 October 2026). It contains the ball bearings of the internal gearbox and the shaft guide. Seals and freewheels are not included. The kit is not a genuine Shimano part. Before buying, check the designation on your motor: the kit is intended for the drive unit DU-EP800. For the Shimano E8000 (DU-E8000) there is a separate overhaul kit PLS00701, suitable for Shimano E8000, €89.95.

More guides: How much does an e-bike motor repair cost? Bearings, belt, freewheel or replacement motor compared · Shimano STEPS error codes: E010, W011 and what is really behind them

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Sources: Shimano, dealer's manual EP800 series (DM-EP800-04): safety notes, installing the chainring unit and crank arms, installing the drive unit. Read on 10 October 2026.