Signs of a bad wheel bearing (and what causes it)

Common symptoms

• Humming, growling or grinding noise that gets louder with speed. It often changes when the vehicle turns, because the load moves onto one side.
• Play in the wheel: lift the wheel and rock it top to bottom. Any clunk or movement means the bearing (or its preload) needs attention.
• Vibration in the steering wheel or floor that increases with speed.
• Uneven or feathered tyre wear on one wheel.
• A hot hub after a drive, much hotter than the other side.
• On two-wheelers: the wheel does not spin freely, or feels rough when turned by hand.

What causes early failure

• Water and mud getting past a damaged seal, especially after driving through water or pressure washing.
• Wrong fitting: hammering on the outer ring when pressing onto a shaft (or the inner ring when fitting into a housing) dents the raceways.
• Wrong preload on taper bearings: too tight and the bearing overheats; too loose and it hammers itself to pieces.
• Old or wrong grease, or mixing incompatible greases.
• Overloading beyond what the vehicle was built for.
• Fake or poor quality bearings. See how to spot fake bearings.

Tips for workshops

• Replace taper bearings as a cone and cup pair, and replace the seal every time.
• Press only on the ring you are fitting, using the right drift or press tool.
• Set taper bearing preload to the vehicle maker's spec, then recheck after a short run.
• Use fresh grease of the right type and do not overfill.

Frequently asked questions