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

Grease the axle threads. To grease underneath the locked cone and locknut, first count the number of exposed threads between the locknut and the end of the axle.

Then unlock the cone and locknut and turn them both to move them along the axle and expose the engaged threads.

Grease the threads, then return the cone and locknut to their original position (same number of threads must be exposed at the end of the axle).

Lock them.

Fig 23

Put a hefty amount of grease in both races.

Last Updated: 11/20/2006.

Fig 24

Place bearings in the grease on the drive-side of the hub.

The grease, if there's enough, will hold the bearings in place.

Fig 25

Reinstall the dust cap by pressing it in with your thumbs. Be sure it seats fully all around.

If it won't go in with finger pressure, use a soft mallet to tap it in.

Fig 26

Grease the cone on the axle.

Fig 27

Insert the axle into the hub from the drive-side.

Last Updated: 11/20/2006.

Fig 28

Turn the wheel over and place the bearings in the other side.

Reinstall the dust cap.

Fig 29

Thread the cone on to the axle until it comes into even contact with the bearings.

Fig 30

Install the washer(s) and thread on the locknut (do not lock it yet).

9. Bearing adjustment.

Method 1 - With an axle vise.

Ensure that the drive-side (right side) cone and locknut are locked to final torque. Now LIGHTLY lock the

non-drive-side cone and locknut you just threaded on. "Lightly lock" means snug them together just enough so

they are in solid contact with each other, but are still able to rotate on the axle.

Using the same method as you used in step 2, check the bearing adjustment.

Fig 31

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.

Last Updated: 11/20/2006.

Fig 32

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

It should spin smoothly. If it doesn't, the adjustment is too tight.

Fig 33

With the tightly locked end of the axle (drive-side) pointing down, place the wheel in the axle vise.

Make sure you place the axle in the appropriately sized hole and tighten the clamp enough so the axle can't spin.

Fig 34

To tighten your bearings, use your adjustable wrench to turn the locknut clockwise.

Since the cone and locknut are lightly locked, they will move together.

Last Updated: 11/20/2006.

Fig 35

To loosen the bearings, use your cone wrench to turn the cone counterclockwise.

Since the cone and locknut are lightly locked, they will move together.

Make small adjustments and remove from the vise each time to check for play or roughness. Continue making

small adjustments until the bearings run smoothly with a minimum of play.

Note: The bearings will get a tiny bit tighter when the wheel is installed on the bike and the quick-release closed.

(The front axle tends to compress more than the rear axle when tightened down in the dropouts. Therefore the final front hub adjustment should have slightly more play than the final rear hub adjustment with the hubs out of the dropouts.)

Fig 36

When you achieve proper adjustment, return the wheel to the axle vise and lock the cone and locknut completely.

Hold the cone in place with your cone wrench and lock the locknut to it by turning it clockwise.

Be sure to keep the cone perfectly still or else the adjustment will change.

As mentioned above, the bearings will get a little tighter when the wheel is mounted on the bike. This is because

the pressure of the quick-release compresses the axle/bearing assembly.

A perfect adjustment will have a slight amount of play out of the dropouts which will disappear when the skewer is

closed/tightened completely.

Bearing adjustment (continued).

Method 2 - Without an axle vise.

Ensure that your drive-side cone and locknut are locked to final torque. Now LIGHTLY lock the cone and

locknut you just threaded on. "Lightly lock" means snug them together just enough so they are in solid contact

with each other, but are still able to rotate on the axle.

Using the same method as you used in step 2, check the bearing adjustment.

Fig 37

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.

Last Updated: 11/20/2006.

Fig 38

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

It should spin smoothly. If it doesn't, the adjustment is too tight.

Fig 39

To tighten the bearings, hold the drive-side (locked) cone with your cone wrench.

Tighten the opposite locknut (clockwise) with the adjustable wrench.

Observe that the lightly locked cone/locknut pair move together along the axle.

Since these are only lightly locked, no damage will occur.

Only if the cone compresses excessively on the bearings will the locknut rotate more than the cone and begin to tighten up on the cone.

Fig 40

To loosen the bearings, hold the drive-side (locked) locknut in place with your adjustable wrench.

Loosen the opposite cone (counterclockwise) with the cone wrench.

Observe that the lightly locked cone/locknut pair move together along the axle.

Since these are only lightly locked, no damage will occur.

Make small adjustments and check each time for play or roughness. Continue making small adjustments until the

bearings run smoothly with a minimum of play.

Note: The bearings will get a tiny bit tighter when the wheel is installed on the bike and the quick-release closed.

Fig 41

Now lock the slightly locked cone and locknut a little more.

Do not lock them completely. If you lock them completely right now, the adjustment will loosen and you'll have to unlock them and try again.

Check the bearings for play and roughness again, and make the necessary adjustment using the above method.

The idea is to zero-in on the correct adjustment by repeating the above steps: locking a little more, checking,

and adjusting. You should never have to unlock the cone and locknut.

Continue this process until the cone is locked completely and the bearing adjustment is correct.

As mentioned above, the bearings will get a little tighter when the wheel is mounted on the bike. This is because

the pressure of the quick-release compresses the axle/bearing assembly.

A perfect adjustment will have a slight amount of play out of the dropouts which will disappear when the skewer is

closed/tightened completely.

Last Updated: 11/20/2006.

11. Install wheel.

If your hub had rubber dust boots, reinstall them. Reinstall the skewer or axle bolts and mount the wheel in the

frame.

Check the hub adjustment by grabbing the wheel at the rim and wiggling side to side. There should be no knocking

or movement.

Spin the wheel and place your fingers near the dropout to feel for any vibrations signaling roughness in the

bearings. Also, watch the wheel as it slows its rotation. It should come to a gradual, smooth stop and swing back

in the opposite direction a few times.