When gear and brake controls and electrical wires (if any) have been disconnected and the wheel removed from the cycle frame , dismantling of the hub begins with the removal of the left-hand locknut, the washers (if any) and the left-hand cone. A note should always be made of their order and number so that they may be put back correctly when the hub is re-assembled. In particular, different numbers of spacer washers may be fitted, depending on the spacing and chainline.
|Left Axle Nut
HMW155 or HMW494
Where a brake is incorporated in the hub, the brake unit must be removed before the left-hand cone can be unscrewed. The last washer to be taken off before coming to the brake plate is the notched adjusting washer which fits over the flats on the end of the cone for normal wheel adjustment purposes. When this notched washer has been taken off, lift out the brake arm and shoes as a complete unit, and then proceeds to unscrew the left-hand cone.
Next, use a hammer and punch to unscrew the right-hand ball ring
As you withdraw the internal assembly, try to avoid touching the low-gear pawls while the unit is held sprocket-side up, because there is a risk of the pawl pins falling out if you relieve the spring tension that holds them in place.
The right hand ball ring has a two-start thread and must be replaced in its original position, that position must be marked. String or adhesive tape may be attached to the spoke nearest to the letters ' SA' which are stamped in one of the notches on the ring. The whole internal can now be withdrawn from the hub shell. (This is rarely a problem in practice.)
This is a standard right-hand thread, turn it counterclockwise to remove it.
Removal of the right-hand ball ring in the case of the TCW is described the chapter headed To Dismantle the TCW Hub.
In all other cases, the right-hand ball ring, which has a right-hand thread, is loosened by means of a 'C' spanner or a hammer and square-ended punch against one of the notches. If it is required to remove the sprocket, insert a thin screwdriver in the groove of the driver which comes nearest to the opening in the circlip and prise off the circlip. The spacing washers, sprocket and outer dust cap may then be lifted off the driver. There must always be two 1/16" washers. Careful note should be made of their position and also whether the sprocket offset is facing inwards or outwards, as they must all be put back in the same way in order to maintain the original chain line.
|Articles by Sheldon Brown and others|
Last Updated: by Harriet Fell