Like the title says, I have an old refurbished bike from the 50's I want to get working again. It has a Sturmey Archer 3 speed shifter and internal gear hub, and that's about all I know about it. It has "Armstrong" printed a few places on it, but no specific model name or number. I need to totally replace the shifter cable and indicator rod, as they've rusted and broken to unusable pieces. How can I make sure I order parts that will be compatible with it? Are there specific types or sizes of Sturmey Archer cables/rods that I'd need to be sure I get in order to be compatible with the bike, or should any 3 speed rod and trigger shifter cable work with it? Like I said, the pieces have disintegrated so I also don't have the originals for reference.
2 Answers
Yes, the indicator rods come in many lengths and several thicknesses. They're inexpensive and available, but figuring it out from scratch can be a pain. The way it works is that there is only one length that will correctly align with the hub reference points for the purpose of adjusting the shifting, but there will be other lengths that can be made to work if one is willing to adjust by feel/sensation.
The best source of this information I know of is Sheldon Brown. Sunrace (Sturmey) may have some free documentation as well, even for old hubs.
Nathan has given you a good starting point from a practical perspective.
As to whether this is a good idea: I have used non-indexed friction shifters i.e. bar end shifters and SR Suntour 'thumbies' to shift sturmey archer 3 and 5 speed hubs for various projects. They work fine, the only caveat is that there is a pretty big 'gap' between clutch plate engagement points on 3 speeds in particular so it's possible to drop the hub into 'neutral' unexpectedly. This can cause quite a big jolt as there is no resistance to pedalling. Some care and feel is needed in shifting, and it's best to avoid shifting under load so no racing with this setup..
As long as you're comfortable with this (in my opinion minor) risk it can actually be a workaround for the issues Nathan mentioned regarding the precise length of indicator rods because you don't have to match the indexing of the shifter with the specific hub.
