If your wheels feel rough when you spin them, it's time to service your hubs. Usually the problem will be caused by wear in your bearings or by the ingress of water and grime. Wheel bearings also wear out over time which will introduce play to the hub, allowing the wheel to rock side to side on its axle.
There are two types of bearings commonly seen in hubs, sealed (cartridge) bearings and non-sealed (cup and cone or loose) bearings.
Regular servicing can extend their life, although they will eventually wear out to the point that they need to be replaced.
How to service your bike's hubs
Cup and cone hubs
You will need:
- Cone spanners - usually 15 and 17mm
- A magnetic hex screwdriver or pick
- A chainwhip and chain removal tool
- Adjustable spanner
- Paper cloth or clean rags
Undo the lock nut on the non-driveside by using a cone spanner to hold the cone and another to undo the nut. Remove the locking nut and spacer by hand.
It’s a good idea to take note of the order in which the locking nut and any spacers are removed to ease re-assembly later
Hold the lock nut on the drive side with one spanner, then undo the non-driveside cone with the other and wind it off by hand. You should now be able to remove the axle from the hub.
Step 2: Carefully remove the bearings from the race - a magnetic screwdriver will help you to lift the bearings out.
You’ll now need to clean the bearings. Use a degreaser and some paper cloth, making sure you fully clean away all the old grease before proceeding.
Take a close look at the bearings, the cups (which is pressed into the hub) and the cones. If there’s sign of wear on them, they'll need replacing.
Note: The cups in Shimano, and many other clone hubs, are non-replaceable. If they have worn out, you will have to rebuild a new hub into your wheel.
Step 3: Take some grease and apply a healthy dose to the bearing race in the hub. You can now place the bearings into the grease which will help hold them in place. Again, a magnetic screwdriver makes this job much easier.
When all of the bearings are in place, you can then refit the axle and gently turn it to ensure they are installed correctly. Remove the axle then repeat the process on the other side.
Step 4: Now return the axle to the freehub side. Press it against the bearings and rotate it to check it’s seated correctly. Refit the cone to the non drive side of the axle and tighten it until contacts the bearings. It doesn’t need to be very tight - finger-tight will do.
You can then spin the axle to make sure it rotates cleanly. Give the axle a little wiggle to ensure you have eliminated any play.
You may need to adjust the tightness of the cone to stop any play or drag - if it’s too tight the hub will not spin freely and conversely if its too loose there will be play in the axle. This step take a little trial and error, but don't rush it as a poorly adjusted hub is likely to cause issues in the future.
Return the other nuts, spacers and seals to the non drive side of the axle, referring to your notes of which order they were removed in.
Then while holding the cone in place, use the other spanner to tighten it against the locking nut. It’s important to check the axle still rotates freely at this point as it’s very easy to tighten the cone also during this procedure.
Step 5: Finally, refit the cassette to the freehub body, replace the quick release skewer and return to the bike.
Cartridge bearing hubs
- Multi-sized cone spanners: 13, 14, 15 and 16mm
- Open-ended 15mm spanner
- 5mm Allen keys
- Solid rear axle
- Nylon mallet
- Small screwdriver
- Bearing grease
- Special tools or alloy tube to press the bearings
Step 1: The axle of your hub will likely have at least one end with a removable dropout guide or locknut which you’ll need to take off. In most cases, this can be done by inserting a 5mm Allen key at both ends and turning anti-clockwise. You might have to put some muscle into it, so use a little cheater bar or a long allen key for this.
Keep track of any washers and their positions between the spacers and axle. The silver spacer doubles as both a dust cap and decorative element in most hubs. It might take some strength to pry off as it will likely be held in by a rubber O-ring between it and a groove on the axle.
Alternatively, some hubs (eg. Mavic) have a threaded cap to allow for bearing adjustment, so just unscrew these first.
Step 2: In order to remove the bearings, you’ll first need to support the hub in such a way that you won’t damage it. For example, you could use a delrin tube of the sort you can pick up from Hope.
You’ll need to strike a few sharp blows to get the bearings out, so a rubber mallet probably won’t do; a resin mallet or a hardwood block with a lump hammer are much better at delivering the force necessary to dislodge it.
Step 3: The next operation removes the bearing which is left behind. Flip the wheel over and position the hub with the bearing facing down. Make sure the hub is sufficiently supported by the flange and there’s room for the bearing to come out.
Carefully position either the axle or a suitable drift tool (an aluminium tube or even an old solid axle with a cone or nut threaded partially onto it will do) and knock the bearing out with a few sharp blows. Be aware that you might have to hit it pretty hard if it’s a tight fit.
Clean the whole hub with a suitable degreaser and a rag, including the hub flanges around the spoke anchor points. Inspect the flanges of the hubs, particularly around the spoke holes for cracks or corrosion. You’ll need a new hub or wheel if cracks are spotted.
Step 4: Spread a light coating of grease on the outside and inside of the new bearings, on the inside of the hub shell and on the axle. If the grease is too thick between the bearing and the hub, it could prevent it from seating completely.
The new bearing should only be driven using the outer race of the bearing as striking the inner race is likely to cause damage to the small ball bearings inside the cartridge.
Use the old bearing or a socket of exactly the same diameter to drive the new bearing in. Keep in mind that the bearing races are made of hardened steel and are therefore potentially brittle. Wear protective goggles and make sure the contact area between the drift edge and the outer race edge is maximised by being perfectly aligned. You’ll know the bearing is seated when the blows suddenly firm up.
Step 5: Refit the axle, position the second bearing and then drive it in with a few blows.
Don’t allow the bearing to go in askew as attempting to force it in if it’s badly out of line will only get it jammed and make it harder to install. It's also likely to create ridges that could prevent it from seating correctly.
Thread the dust caps back on with a little oil, then feel for that well earned, buttery smoothness.