By Eric Murray , Technical Editor Y ou pay attention to you motorcycle's crank bearings, rod bearings and maybe even the steering head bearings. Most modern wheel bearings last a long time. However on high-mileage bikes, or dirt bikes that see a lot of mud and water, and bikes washed with high pressure hoses, the bearings can go out sooner than you think. In the case of our example, a well-used Beta trials bike, the front wheel bearings were completely shot after two years. The bearings were so worn that the wheel could flop around about a half-inch at the rim.
Wheel bearings have a tough life.
They are precision made parts subject to large amounts of stress and need lubrication. Typically, they have to rely on a little grease added at the factory, maybe many years ago. When they run dry or start to rust, they will heat up, wear out of round and develop excess clearance. Most bad bearings aren't immediately obvious, though they will get worse quickly if you ignore the first signs. Or you can feel a grittiness in the bearings when you turn them by hand when the wheel is off for a tire change.