Some motorcycles, and many electric bikes and scooters, drive the rear wheel with a toothed rubber belt instead of a chain. The belt has strong cords inside and teeth that mesh with toothed pulleys on the gearbox or motor and on the rear wheel. It is not the same part as a scooter CVT belt, which is smooth and V-shaped: see CVT belt.
What it does
It carries the drive from the engine or motor to the rear wheel. It needs no oil, runs quietly and stretches very little.
Signs it is worn or failing
- Cracks across the teeth or along the back.
- Missing, torn or rounded teeth.
- Frayed edges, often because the belt runs off centre.
- Ticking, slipping or a jerk when pulling away.
- A hole or cut from a stone trapped against a pulley.
When to replace it
Replace the belt when it has deep cracks, missing teeth or stone damage, or at the interval in the manual. Check the pulleys at the same time: Check a toothed final drive belt.
What to match when buying
- The exact part number for the bike: length, width, tooth count and tooth profile must all match.
- Pulleys with the same tooth profile.
Fitting notes
- Do not fold, twist or kink a new belt, or pry it over the pulley flange. This breaks its cords.
- On many bikes the swingarm or a cover must come off to fit a belt. Follow the manual.
- Set tension with the gauge method in the manual and keep the wheel straight.