Hub overhaul - part identification

Hub with quick-release skewer removed.

Fig 1

The axle assembly as it looks removed from the hub body.

Fig 2

Bearings - the front hub usually has 10 on each side, 3/16" in diameter. Rear hubs usually have 9 on each side,

1/4" in diameter.

Fig 3

Bearing races-these are the surfaces where the bearings contact the hub itself.

Fig 4

Hub adjustment tools (left to right): a strong magnet for extracting bearings, cone wrenches, and an adjustable

wrench good for use on the locknut.

Fig 5

An axle vise - this tool, in conjunction with a standard work bench vise, holds the axle in place to ease adjustment.

Fig 6

Last Updated: 11/20/2006.

Hub overhaul (front)

1. Remove wheel and prep hub.

Fig 7

Open the brakes to allow room for the tire to pass through.

Open the quick-release skewer or unscrew the axle bolts and remove the wheel.

Remove the axle bolts or the skewer.

To remove the skewer, unscrew the adjustment nut and pull the skewer out of the axle. Be careful not to lose the cone-shaped springs at either end of the skewer.

Fig 8

If your hubs have rubber boots on the ends of the hub body, pry them off using a small flat screwdriver.

Last Updated: 11/20/2006.

2. Check bearing play and roughness.

Fig 9

Hold one end of the axle between your fingers and wiggle it side to side and up and down feeling for any movement or knocking.

If you can feel movement, the bearings are too loose.

Fig 10

Next spin the axle with your fingers and feel for roughness.

It should spin smoothly. If it doesn't, the adjustment is either too tight, or the bearings are worn or corroded.

Last Updated: 11/20/2006.

3. Lock one side of the hub.

In order to ease adjustment and re-assembly, it's a good idea to lock the cone and locknut on one side of

the hub. The standard is to lock the drive-side (right side).The locked cone and locknut will remain in place and

ensure that when the hub is reassembled, proper spacing on the axle is preserved.

First, make sure there are an even number of threads exposed on both ends of the axle.

Fig 11

Fig 12

Fig 13

Lock the drive-side cone and locknut by turning them into each other. Use an appropriately-sized cone wrench on the cone and your adjustable wrench on the locknut.

Sometimes the locknut won't have wrench-flats wide enough for an adjustable wrench, and will require a cone wrench as well.

4. Remove locknut and cone from other side.

Fig 14

As you remove parts from the axle, it's a good idea to set them aside in the order they come off and with the same orientation. That way you won't have to reassemble them all by memory.

Last Updated: 11/20/2006.

Fig 15

Now turn the wheel around and remove the locknut and cone from the non-drive-side end of the axle.

To remove the locknut, hold the cone in place and turn the locknut counterclockwise.

Remove the locknut and any washers.

Fig 16

Next, remove the cone.

Keep the side you are working on facing up so the bearings don't fall out.

5. Remove the bearings from the disassembled side.

Keep the wheel on its side so the disassembled end of the axle faces up.

Fig 17

Let the axle fall out just enough to allow the top bearings to come out. Don't completely remove the axle yet or else you may loose the bearings on the bottom side.

In some cases, the bearings can be extracted without dropping the axle. In these cases, you should keep the axle pushed upward to keep the bearings on the bottom side from falling out.

A magnet works best for removing the bearings, but if you don't have one you can pop them out with a screw driver or grab them with pliers.

6. Remove bearings from the drive-side.

Fig 18

Turn the wheel over and pull the axle all the way out.

Then remove the bearings using the same method as on the non-drive-side.

Last Updated: 11/20/2006.

7. Clean and inspect parts.

Ideally, all parts should be cleaned with solvent. If you don't have access to solvent, use a clean rag instead.

It's generally a good idea to replace the bearings unless your hubs are fairly new. Even bearings without any

visible damage may be slightly flattened, and when reassembled will not roll smoothly. Whether you're

going to replace or reuse them, you should inspect the bearings as their condition will give you an idea of the

state of your hub.

Fig 19

To ease cleaning and inspecting the hub races, you can remove the dust cap by prying it out (gently) with a large screw driver. This is optional and if your dust caps prove difficult to remove, just leave them in rather than risk bending them.

On some hubs the dust caps are press fit onto the cones. If this is the case on your hub, then the dust caps will already be off and you can skip this step.

Fig 20

After cleaning, inspect all parts for wear.

The cones will often have a very obvious worn "path" where the bearings contact. Check for any irregularities or pitting in that path.

If the cones show uneven wear or pitting, they should be replaced.

Fig 21

Check the races for pitting and irregularities as well.

Excessively damaged races usually require replacing the whole hub.

Check that the axle is straight by rolling it on a flat surface. A bent axle should be replaced.

Last Updated: 11/20/2006.

8. Grease and assemble.

Use a medium-weight bicycle grease. Park Polylube 1000 works well.

Fig 22