Chances are that very few of you will be replacing wheel bearings or even wheel seals on a regular basis, but that doesn’t mean you shouldn’t know how to do it. Most hubs have sealed ball bearings pressed lightly into the hub. A shoulder machined into the hub or an internal spacer sets the depth of the bearing in the hub.
• Shop manual
• Large brass drift
• 3 lb hammer
• Wheel bearing grease
• Small pry bar
• Circlip pliers
• Bearing drift (optional)
These bearings are not serviceable. When they show any signs of side play, you need to replace them.
While the sealed ball bearing is the most popular, some bikes do use a tapered roller bearing. The tapered roller bearing has the advantage of being adjustable for preload and repackable with grease. Wheel bearings are usually troublefree, although street riders that carry heavy loads or rack up very high mileage may wear them out, as will the average dirt rider.
One thing that’s murder on a wheel bearing is washing your bike down with a high-pressure spray washer or steam cleaner. If you do wash your bike at a coin-operated car wash, avoid directing that high-pressure stream directly at the wheel bearings. Prop the bike up so that the wheel you want to check is clear of the ground. With your hands on the wheel 180 degrees, apart from trying to move the wheel at a right angle to the axle. If the play is felt, you need to find the cause. If no play is felt, great, you’re all done.
If the play is felt, make sure that it’s actually in the wheel bearings by double-checking all of the axle- and wheel mounting hardware. Assuming the play is in the bearings, replace them (if they are sealed) or adjust them (if they are tapered rollers). See your shop manual for the specifics on adjusting your tapered bearings. Start by removing the wheel. The rear wheel may include a separate sprocket carrier with its own seal and bearing.
If so, that bearing and seal should also be replaced or adjusted along with the wheel bearings. Support the wheel so that the hub is clear of the ground by a few inches. A small wooden box will come in handy here. Make sure the hub itself is supported, not just the spokes. The most common type of bearing and hub arrangement will be two ball bearings separated by a spacer and pressed into the hub.
Normally, there will be a seal on each side of the hub that will have to be removed. Gently pry the seal up and out of the hub. Once the seal is out, you’re likely to find that the bearing is retained by a large circlip, or in some cases a threaded ring. Remove the retainer.
If it’s a threaded ring, a special tool may be required, although a punch can usually be used or a tool cobbled up. Insert your long punch through one bearing and pry the spacer to one side. A portion of the inner race of the other bearing should now be visible.
Use your punch to drive against the inner race. Work your way around the race to avoid cocking the bearing in the hub. After the first bearing and spacer are removed, flip the wheel over and remove the bearing on the opposite side. Never reinstall sealed bearings after having driven them out.
Since most bearings are generic, you can save a few bucks by picking them up at your local industrial-supply, auto parts store, or bearing specialist. (Each bearing will have a code number stamped onto it; the number can be cross-referenced by anyone with a bearing catalog.) Inspect the hub for any galling before installing the new bearings.
If the bearing seats are damaged, they should be repaired; minor scrapes and scratches should be polished out with sandpaper. Severe damage may require hub replacement, although a bearing-locking compound like Loctite Stud and Bearing Mount can often be used if the damage isn’t too severe.
Unless the bearing is sealed on both sides it should be packed with high-temperature grease before installation. Install the first bearing using a drift that locates on the outer race. Install any circlip or retainer. Flip the wheel and install the spacer, followed by the second bearing and any appropriate retainers.
Press the seals into place with the open side facing the bearing. Again use a drift that only contacts the outer edge of the seal. Lightly grease the axle and reinstall the wheel.
Read also: How To Maintain Wheels and Tires