Bicycle Wheel Bearing Maintenance

Bicycle hub with traditional cup and cone bearings © Eugene Brennan.

So the back wheel on my bike was making grinding noises on the way back from my cycle along the canal to Sallins last Sunday. These rims are 1997 vintage and older wheels have cup-and-cone bearings. The advantage of these is that the parts can be easily replaced when they wear: the axle, the cones and the steels balls the cones turn against. Unfortunately they're also prone to grit and grime getting into the bearing, especially when a hose or power washer is used to wash muck off a bike, as this can drive the stuff inside. Newer hub bearings are sealed and probably use roller or ball bearings. However when the bearing wears, the whole wheel has to be replaced. The hub and axle alone can be replaced, but it means undoing all the spokes, then rebuilding the wheel with the new hub and replacing the spokes, which is not a job for amateurs. That's because all the spokes have to be properly tensioned to ensure trueness of the wheel.

I cleaned all the balls from the bearing (a magnetic pick-up tool is the best way of getting them out of the grease), the cones and the cups which are bowl-shaped steel inserts in the aluminium hub. Neither were excessively pitted nor worn. The axle was a bit bent, but that often happens due to impacts with a bad road surface and applying too much force to pedals when climbing steep hills. Then I re-greased everything and put the bearing back together. It's still a bit rough, but should last for another while. I have a spare pair of new sealed bearing wheels to act as replacements.

Spacer to accommodate freewheel cogs. © Eugene Brennan

Components from bearing. © Eugene Brennan

Trainee bicycle mechanic. © Eugene Brennan

Cup part of cup and cone bearing. © Eugene Brennan