Bearings
About Bearings
Bearings let the gearbox shafts and the wheel hubs spin freely while holding everything in position, and a failing one usually announces itself with noise. Riders shop here for a transmission bearing kit during a rebuild, a worn inner primary or main shaft bearing, or a set of wheel bearings with their spacers.
Parts here are very model specific. The transmission bearing kits in the samples are listed for particular dirt bikes, such as the Suzuki RM 250, Kawasaki KX 85/100/112 and Gas Gas, Husqvarna and KTM models, while the Harley-Davidson parts are listed for Big Twin, Sportster and Shovelhead years. Wheel bearing kits and wheel spacer kits are listed by model too, and the spacer kits come in front and rear versions. Replacing a transmission bearing often means splitting the engine cases, so plan the job with the service manual or hand it to a shop. Renew the seals at the same time.
Brands in this category include Hot Rods, Jims, Emerson, S&S Cycle and All Balls. Pick your machine in the Ride Finder at the top of the page to see kits made for it. Seals and gaskets are in Gaskets & Seals, and the gears and shafts the bearings support are in Gearbox & Transmission Parts. See also Clutch Parts & Kits and the parent group Transmission & Drivetrain.
FAQs on transmission and wheel bearings
What does a failing transmission bearing sound like?
A rumble or whine from the gearbox that changes with engine speed or with the gear selected is the usual sign, and so is fine metal in the drained oil. Have it inspected early, because a worn bearing lets shafts move and can damage the gears.
Why do wheel spacer kits come in front and rear versions?
Spacers sit in the wheel hub or beside the bearings and set where the wheel is held between the fork legs or swingarm. Front and rear wheels use different widths and hub designs, so each has its own spacer, listed by model and year.
Should I replace both wheel bearings at the same time?
Yes. Both bearings in a wheel carry the same load and age together, so replacing only one leaves the other likely to follow. Wheel bearing kits are sold as sets. Check for roughness or side play whenever the tire is off the bike.
How do I install a bearing without damaging it?
Press or drive it in with a tool that touches only the race being fitted: the outer race when it goes into a housing, the inner race when it goes onto a shaft. Hitting the wrong race can dent the balls or rollers, so keep the bearing square as it goes in.
How do I find the right bearing for my machine?
Use the Ride Finder to pick your year, make and model, then check the listing against the part number in your service manual or on the old bearing. Bearings of similar size can differ in type and seal style, so do not choose by size alone.
