Henry Szeto has borrowed a CCM mountain bike from a friend for the summer, and he is getting a lot of squeaking from the rear wheel at the axle. I asked Alan Medcalf what Szeto should do. He replied:
"On a CCM or other inexpensive bike, the hubs will most likely have serviceable ball bearings. These bearings require bicycle grease rather than oil, which can migrate out of the bearings, leaving behind a gritty paste which quickly clogs up the bearings. When this is dried out as well, the bearings will rust and start squeaking...
"As a general rule of thumb, hub bearings ought to be overhauled at least every other season for lightly-used bikes, and more often for bikes used regularly or in dirty, muddy or rainy conditions. A commuter bike may require hub overhauls two or three times a year.
"It’s easy to tell whether your hub bearings need overhauling. First, spin the wheel and ensure that it doesn’t have any wobble that causes the rim to rub against the brake pads, or the tire against the frame. If this is happening, have your local bike shop repair the wheel first. It may just need truing, or there may be loose or broken spokes, or the rim may be bent.
"If that’s not the problem, next grab the wheel at the top and with the other hand on the fork (front) or seat tube or seat stays (rear), try and wiggle the wheel back and forth sideways. If the hub seems loose or 'knocks' against the axle, then the bearings need adjusting and may as well be overhauled at the same time."If you try to spin the wheel and it spins with difficulty, or slows down quickly instead of spinning on and on, then there’s lots of friction in the hub, and it needs an overhaul. Another good test, with the wheel off the bike, is to hold the wheel steady and rotate the axle with your fingers. If it doesn’t feel silky smooth, if there’s resistance or it feels gritty or hard to turn, the bearings need overhauling.
"Unless you know what you’re doing, a hub overhaul is a job for the mechanic at your local bike shop. It involves disassembling the hub, cleaning all the parts, packing with fresh bicycle grease, putting in new balls, reassembling, and adjusting the bearing preload correctly. It’s important that the grease is formulated for bicycle use. It’s lighter than automotive grease, and designed to work best for the conditions found in cycling."