Sturmey Archer Repair: Replacing Splined Sturmey Archer Cups/Ratchets

I've written previously about removing and replacing old-style Sturmey Archer non-drive sized cups/ratchets. In the early 1960s, Sturmey Archer went from a threaded cup and ratchet assembly on the AW hub to a splined assembly pressed into the shell. How to remove them?

Removal of splined cups/ratchets is fairly straightforward but requires some care. The hub must first be emptied of its contents in the usual way. (A guide to disassemble the AW and other Sturmey Archer hubs is available in various places on the internet, including Tony Hadland's site and Sheldon Brown's site).  

Next, the hub must be properly supported at the base of the flange. At the minimum, the hub must be carefully mounted on top of a solid vise so to maximize the contact area on the flange of the hub. Ideally you would have a close-fitting block of hardwood that contacts the entire flange, thereby distributing the force evenly. But in this case, I have the hub carefully set on the vise jaws. There is a substantial risk of damaging the flange if too little of the flange surface contacts your blocks/vise jaws. 

If the hub is mounted in a wheel, you can use the rim to hold the wheel and for leverage. This job is a bit easier with a whole wheel, but it can be done with just the hub mounted in the vise/blocks. 

Moderate heat is applied by a propane torch around the line where the cup/ratchet piece meets the hub shell. A small amount of Kroil or similar penetrating oil can be dropped into the joint from the top.

Next, a close-fitting punch (1/8 inch in my case) is used to punch-out the ratchet/cup from the top using moderate blows from a hammer onto the punch, and working evenly around the lip of the ratchet ring. Be careful that the punch stays on the lip and does not slip off, which can damage the ramped ratchet surfaces or the hub shell interior. Keep warming the joint and applying oil as needed. Once the ratchet/cup starts to push out, it will gradually get easier to move. You can lighten your strikes with the hammer on the punch as it pushes out. 

 

Once taken apart, you will see the spline teeth. Clean and inspect the teeth. They need not be perfect, but they should be fairly sharp and there should not be ground-down or missing teeth. Also inspect the hub shell teeth/splines. 

Re-assembly is straight forward. A good splined ratchet/cup should be sourced and pressed into place in your shell carefully using a bench vise padded with some wood blocks. A little grease helps prevent galling, but don't make a mess. You want the new cup/ratchet firmly in-place. Remember that your hub depends on those teeth grabbing and locking the cup/ratchet into place. 

I personally prefer the older, threaded style of cup that works with a bench vise and unscrews. However, it is possible to replace the splined type with a little patience and care.