I see on the 'net it's been done but no info on how or even a decent picture of it. Has anyone here any insight please? It'd be a neat solution to a low range for hillclimbing a 30kg trike.
When I was a teen in Devon, I saw it done a few times when I visited the big city (Barnstaple!) I think that you needed parts from a Sturmey Archer three or four speed hub that had the built in dynohub or drum brake in order to get the spindle length.
Sachs/Sram do a hub usually 3 x 7 or 3 x 8 called a Dual drive ?
I have one NOS not laced into a wheel and one in the Nazca Fiero seems to work ok makes the wheel heavy and a bit harder to remove should you get a puncture ?
Sturmey Archer still do a 3-Speed with Cassette hub. I had 3 x 8 on mine. It is currently in a 26" rim.
The 3-Speed is 75%/100%/133% as per standard. Its ok, but on an e-bike the pawls can slip under load.