Electric scooter bearings: noise, play, and replacement, including the motor

A worn bearing on an electric scooter can be identified by three signs: a grinding noise that increases with speed, play when the wheel is shaken from side to side, and a rotation that feels rough or "grating." The bearings that experience the most stress are those in the motor-wheel assembly, which bear the weight of the scooter and the rider and absorb the shocks from the road. Replacing them is relatively simple on a freewheel, but more delicate in a motor due to its powerful magnets. This guide explains how to diagnose the problem and when to entrust the work to a workshop.

Where are the bearings on an electric scooter?

• Inside each motor-wheel: Typically, there are two bearings, one on each side, mounted on the fixed shaft. The motor rotates around these bearings.
• In a non-drive wheel, on single-motor scooters.
• Steering Direction: Two bearings allow the fork to rotate within the frame. Their case is addressed in our guide on steering column play.
• In some suspensions, bushings are used at the joints of the arms; others use simple friction rings.

Identifying a worn-out bearing

The noise

A damaged bearing produces a rumbling or low humming sound that increases with the wheel's speed. The test that helps: start the scooter, then release the accelerator. If the noise remains the same in free-rolling mode, it likely comes from a bearing; if it disappears when you release the accelerator, it is more likely related to the motor or the controller. Other noises (clacking, whistling, clicking) have different causes, which we review in the guide motor noises and clacking sounds.

The game

If the wheel is off the ground, grab the tire from the top and bottom and try to rock it from side to side. A slight clicking sound indicates play. First, make sure the axle nuts are properly tightened: a loose axle can give the same sensation.

The rotation

On a non-powered wheel, rotate the wheel by hand: it should turn freely, without any stiffness or grinding. On a motor wheel, it's more subtle: the magnets create a slight, regular "stepping" effect, which is perfectly normal. A bearing that is nearing the end of its life will add a rough, irregular friction that you can feel in addition to these "steps."

Why do bearings wear out?

• Bearing Wear: A heavy scooter, a rider carrying equipment, and repeated impacts can wear down the bearings and their races.
• Water and dust: they gradually penetrate the seals, wash away the grease, and cause the bearings to rust. Our guide electric scooter and rain details these points of water ingress.
• High-pressure washing: A powerful jet of water directed at the axle forces water through the seals.
• Incorrect axle tightening or missing spacers, which cause the bearing to be misaligned.
• Heat: A motor that gets very hot causes the grease in its bearings to degrade more quickly.

Choosing the right bearing

The reference of a bearing is engraved on its surface: a series of numbers that indicates its dimensions, often followed by a suffix that indicates its protection. By convention, "2RS" designates a bearing sealed with two rubber seals, and "ZZ" indicates a bearing sealed with two metal shields. Rubber seals offer better protection against water and dust; this is the type we prefer for a scooter that is used outdoors. Always replace with a bearing of the same dimensions, from a reputable brand: a low-quality bearing can quickly fail under the load of a motor wheel.

Replacing the bearings in a motor wheel

In a motor-wheel, the magnets in the rotor are very powerful. When opened, they strongly attract the stationary part (the stator), which can pinch fingers, scratch the windings, and even chip the magnets. The work involved requires:

• to disconnect the power supply and unplug the motor;
• to disassemble the wheel and, often, the tire;
• To open the motor, use a suitable extraction tool, ensuring it is properly aligned with the motor shaft
• to remove the old bearings and press in the new ones without hitting the balls
• to avoid damaging the cables that run through the axle or their cable guides
• Properly reseal the motor, ensuring its watertightness.

The internal workings of a hub motor are explained in our guide on hub motors. If you don't have the necessary tools, entrust this work to a workshop; at our shop, you can book labor services in 30-minute increments.