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Inspecting your bike’s bearings: what to do if these parts aren’t turning at their best

By Nick Di Cristofaro

Where are the bearings on your bike? You’ll find them anywhere parts need to turn. Wheels? Yup. They spin, so at their centre, the hub has bearings. What else rotates? Your crankarms, pedals and steering tube when you push on the handlebars. Also, your chain is actually a bunch or bearings linked together. The rollers rotate about the pins on a chain. There are also bearings in the linkage of your full-suspension mountain bike.

Checking the bearings in the wheels, bottom bracket, headset and suspension

Most hubs have cartridge bearings. I would refer to one of these as cartridge ball bearings because tiny metal balls are encased in grooves between an inner and outer race. The axis of rotation—such as the hub axle or shaft of your crankset—rotates the inner race which then spins the tiny balls along the outer race. This action is what reduces the friction and allows you to sail down the road or trail. The cartridge bearing has a close cousin in certain hubs called the cup-and-cone bearing. It has balls that sit in an inner (cup) and outer (cone) race, which can be taken apart easily. You can actually clean the metal balls and races and then apply fresh grease. This setup is most common in older hub designs, but they are still a mainstay in Shimano hubs and some Campagnolo ones as well.

Cartridge bearing

Before you inspect the bearing on your wheels, make sure the quick-releases or thru axles are tight. Grab each wheel rim and try to wiggle it side to side. There shouldn’t be any play. If there is play, first try adjusting the hubs, if that’s an option. (Some hubs can’t be adjusted.) Check with the wheel manufacturer’s dealer or service manual for the best method of adjusting your particular hubs. If this fix doesn’t get rid of the play, the movement is due to worn bearings. Rotate the hub axles and feel for smoothness. If it feels gritty and rough, the hub must be disassembled and inspected. Parts might need to be replaced. Best to leave these steps to the professionals at your favourite local bike shop.

Checking on the bearings in the bottom bracket is much like the process for the hubs. Grab the crankarms and check for play. Try to get rid of the play with a crankarm adjustment. If there is still movement, then remove the cranks and inspect. Some bottom brackets will have replaceable bearings and some will not. Also, look for rust and corrosion, which could have caused the wear. Rotate the inner bearing race with your finger and watch for play. If it is excessive, it is time to replace the bearing or even the bottom bracket assembly.

To check the headset, rotate the handlebars. Feel for any grittiness or roughness. Make sure the bars do not “hang up” or get stuck in one spot. Try an adjustment first. If this step doesn’t solve the issue, the headset will need to be serviced and bearings inspected or replaced. A good preventative measure is to clean and grease the headset periodically. For common threadless designs, this is a simple procedure of disassembling, cleaning and greasing the areas of contact between the frame, steering tube and bearings.

If your bike has suspension, remove the rear shock. Work the suspension through its range of travel, checking for play and grit. If you find them, it’s time to get your suspension serviced.

Cleaning cartridge bearings

If you are comfortable with tinkering, you can clean and maintain cartridge ball bearings. This maintenance is most beneficial when you are dealing with expensive ceramic bearings in your wheels or bottom bracket. With steel bearings, I feel it’s best to simply install new ones as they are fairly inexpensive.

Leave your cartridge bearing installed during maintenance. If you remove it, you risk damaging it. Using a new razor blade, remove the outer seal very carefully. Do not bend the seal. You must use the edge of the blade at an angle to pry off the seal gently. Once the seal is off, you can clean and lubricate the balls and they sit in. Clean with a degreaser and allow to dry. Then, oil or grease the balls and races. Usually, greasing is the best option. Some special bearings will require a certain grease or oil so always check the service manual. If you are after every little last marginal gain, then don’t replace the seal. I don’t recommend this though, unless you only race on dry days or have an unlimited budget. It’s best to seal the bearing back up, and keep it spinning for as long as you can.

This story originally appeared in the April/May 2022 issue of Canadian Cycling Magazine