A rumble, growl or grinding noise comes from the front or rear and rises with road speed, not engine speed. It continues when you pull the clutch in and coast. A worn wheel bearing is a common cause, but dragging brakes, a cupped tyre, a dry chain or a speedo drive can sound the same. This check separates them.
Is it safe to ride?
With care for a short distance if there is no play in the wheel. If the noise is grinding metal, or the wheel has play, do not ride.
Quick checks first
- Coast with the clutch in: does the noise stay? Then it is from the wheels or chain, not the engine.
- Does the noise change when you lean left and right? Bearings often change tone when loaded.
- Touch the hub after a ride (carefully): is one much hotter than the other?
- Look at the tyre: cupped tread hums too.
- A hub that is very hot after a ride, with the brake not dragging, means the bearing grease has failed: Wheel hub or brake drum is very hot after riding.
Diagnose it step by step
1Lift the wheel and rock it top and bottom. Any play?
- Yes: go to Wheel moves sideways on the axle.
- No: go to step 2.
2Spin the wheel by hand. Does it slow down quickly, or do you hear a regular swish or scrape once per turn?
- Yes: a brake is dragging. Check for brake drag, see Brake drags.
- No: go to step 3.
3Rear: take the chain off the sprocket (or slacken it fully) and spin again. Has the noise gone?
- Yes: the noise is the chain or sprocket. See Chain is noisy.
- No, or front wheel: go to step 4.
4Spin the wheel with your fingers on the fork leg or swingarm next to the hub. Do you feel a rough, gritty vibration?
- Yes: the bearing is worn. Check wheel bearings, then Replace wheel bearings.
- No: go to step 5.
5Front with a mechanical speedo: disconnect the speedo cable and spin. Quieter?
- Yes: the speedo drive or cable is dry or damaged. Replace the speedometer cable; grease the hub drive when the wheel is out.
- No: go to step 6.
6Is the tyre cupped or worn unevenly?
- Yes: the hum may be the tread. See Tyre worn into a scalloped or cupped pattern.
- No: remove the wheel and check the bearings off the bike. On the rear, also check the sprocket carrier and cush drive (Check the cush drive rubbers).
7. Electric hub motor? Noise from the motor itself: Grinding, clicking or growling from the motor.
Causes, most likely first
| Cause | How to confirm | Fix |
|---|---|---|
| Worn wheel bearing | Rough feel when spun, no drag | Replace wheel bearings |
| Dragging brake | Wheel slows fast, swish per turn | Brake drag check |
| Chain or sprocket | Noise gone with chain off | Chain slack and lube |
| Cupped tyre | Stepped tread blocks | Inspect tyres |
| Dry speedo drive | Quieter with cable off | Speedo cable |