On a car, the bearings provide support to the car body from the wheel
axles.
This means that while the car is being driven on the road, the bearings are subject to wear.
Manufacturers often recommend that bearings are changed at a major service. If the bearings wear through, the car will become undriveable without doing a serious amount of damage to the chassis. If front wheel bearings fail, you will lose control of steering, and the wheel may well come off.
Early warning signs
If the car develops a
resonance which varies with the road speed, this may indicate a bearings problem, having eliminated the obvious - flat tyre, unusual road surface. Disengage the transmission by depressing the
clutch or moving the
shift into neutral. If the noise remains, it is not engine or transmission related.
Neglecting tracking causes greater wear
It's a good ides to have the
wheel alignment checked at mileage intervals recommended by the manufacturer. Otherwise the bearings will be unevenly loaded, and wear more quickly. You will also need to check and potentially readjust the alignment after changing any bearings.