How to check and replace wheel bearings

By MCN Technical Staff -

Parts & accessories

 29 November 2006 15:18

Why bother?

Worn or damaged wheel bearings will cause: (1) ill handling with weaves and wobbles, a bit like a flat tyre, and (2) ill health if a wheel bearing collapses and the wheel cocks to one side to lock the chain up. These are valid reasons why you should check wheel bearings on a regular basis, say every time you lube the chain or clean the bike.

What you’re dealing with

Removing and replacing worn parts which we depend on to make the wheel go round. Wheel bearings are susceptible to water damage from pressure washers and dirt even if they are sealed bearings (metal, rubber or plastic shields).

Don’t think about it if…

You lay awake at night wondering if you locked the back door – you’ll never sleep at night again as you agonise over whether you knocked those new bearings in square or not...

Stuff you’ll need

A socket set (8-17mm minimum), combination spanners (8-19mm), torque wrench, a socket for the wheel spindle nut, hammer, front and rear paddock stands. Most important is a drift to knock the bearings out (steel shaft of about 5mm thickness and 180mm in length) – an old clutch push rod is ideal. If money is no object a bearing driver set for fitting the new bearings. Otherwise, retain the old bearings or buy a socket whose outer wall is the same size as the outer bearing cage.

What can go wrong?

Someone could flog you the wrong bearings. Always replace bearings with the exact same type.

What skills do I need?

A fair amount of mechanical aptitude – if you can remove and refit the wheels and brake system you’ll breeze this.

1. Check the wheel bearings on a regular basis by placing the bike on a stand (front or rear) and firstly making sure the wheel spins freely. At the rear, if the chain is tensioned and lubed correctly and the sprockets are in good nick, all you should hear and feel (with one hand resting on the swingarm) is a smooth rumble of chain over sprocket teeth.

2. Next firmly grasp the top and bottom of the tyre from the side and try to rock the wheel backwards and forwards. Make sure the bike is not wobbling about on the paddock stand – get a friend to sit on the bike or hold it steady. Turn the wheel 90° and do the same again. Carry on until one full revolution of the wheel is complete.

3. Play in the bearing(s) will be felt as a slight movement of the wheel. If the bearings are shot completely it will be a large movement and felt and heard as a clunk. Check that the wheel spindle isn’t incorrectly tightened as this can lead to similar symptoms. If it’s OK, then one or more bearing is knackered. Replace them all, as it’s best to play safe.

4. Remove the rear wheel in the normal way and pull out the rear sprocket carrier and any cushdrive rubbers (the bike pictured doesn’t feature these parts). If there is a carrier, it also will have its own bearing that needs checking. Does it turn freely? Can play be felt in the inner race? Are there signs of steel discolouration from overheating?

5. Lay the wheel flat, supporting the rim on wood blocks. Inside the hub is a tubular spacer to stop the bearings distorting as the spindle is tightened. Designs vary but the spacer here has a big washer welded half way along it to keep it in place in the hub. Knock the spacer off-centre at one end by tapping it with the drift as shown.

6. Now the spacer should be slightly out of line with the bearings. Doing this means that when you go to tap each bearing out, using a long drift from the opposite side, you can get contact with the bearing’s outer race (some hubs have indents to help do this). If you can’t, then place the drift against the inner race. Now start to tap the bearing free.

7. When the bearing starts to move, tap it equally around the circumference of the outer race to ensure the bearing doesn’t twist and damage (enlarge) the hub. When it is out, turn the wheel around to remove the other bearing in the same way. If the spacer tube falls out, don’t panic.

8. If the bearings are different each side, note which one goes where. Check the code numbers (usually seen on the black seal section) on the new bearings match the old ones. This is extra important if you’re saving cash by buying direct from a bearing maker (try the Yellow Pages) instead of ordering a genuine part from your bike dealer.

9. If the bearings are the non-sealed type (eg you can see the balls) turn the outer race while holding the inner and pack a little extra grease in. Sealed bearings come pre-greased. Now align one new bearing in its seat in the hub and put the old bearing, or a socket, on top of it. This lets you tap the new bearing into place with less risk of damage.

10. Turn the wheel over. Reinstall the inner spacer tube (pictured above) and fit the second new bearing to the opposite side of the hub, following the same process as described in step 9.

11. Check the spacer tube is aligned (co-axially) with the bearings so the spindle can pass through freely. In the picture above it’s slightly off-centre and needs tapping into position (like step 5 in reverse). Both bearings should grip the spacer lightly where it touches the inwards-facing surfaces of the inner races. A little patience should get the alignment/position spot-on.

12. Refit the cushdrive rubbers and sprocket carrier (with its new bearing, if needed), plus any spacers (make a note in step 3 of their orientation) then refit the wheel. Torque up the wheel spindle nut (ask your dealer for the figure). NB: Early Yamaha R1 rear wheels have roller bearings, which need special tools for removal and installation.