Bicycle Repair Cleaning and repacking a hub

< Bicycle repair

 

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Over time the wheel hubs of a bicycle may come out of adjustment causing the wheel to wobble from side to side (this can also be the result of the wheel being out of true; close examination of what happens at the axle when the rim is wiggled from side to side will differentiate between the two cases). Additionally, road dirt and miosture infiltrate the bearings, causing rough operation and premature wear. Even if these issues do not arise, the bearings' lubrication will eventually need to be replaced in order to maintain the life and health of the hubs. These problems can be addressed by overhauling the hubs. The basic techniques are similar to maintaining any other ball bearing assemblies, whether the headset or bottom bracket on the bike, or on complete different applications.

On some recent model mountain bikes, there has been a rash of rear hubs getting significant play after only a few rides; this may be due to bad cones or lock nuts. The drive side lock nut should be your number one suspect in this case if the bike is new.

Parts of the hub

From the inside out:

Shell

Holds the axle assembly and is the connection point for the spokes.

Bearing Cup

Is pressed into the shell.

Bearing Cone

Forms the inside of the bearing race

Bearings

There are three major types of bearings in use on bicycle hubs:

Cone and Cup types

Cartridge type

Cleaning and repacking a hub

For a traditional cone and cup front hub

At this point, depending on how the grease is distributed on the parts, the ball bearings may well stick to the axle, or drop out of the hub or into the axle hole through the hub, or remain in the cup. If the bearings are in a cage, they will generally remain in place unless the cage has been excessively worn.

It is advisable to leave the other cone and locknut assembly undistrubed in its position on the axle, as this will allow you to maintain the original side to side alignment of the axle assembly in the hub as much as possible. (Of course, this is mandatory where this assembly is not removable). It can be cleaned and greased in this condition. (If the cone is damaged, then it will need to be disassembled and replaced).

 

 

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