I'm afraid that the 8 speed SA hub was a poor choice for a bike with 27" wheels. The hub was designed for 20" wheel bikes and first gear is 1:1. Usable gearing requires the use of a chain ring that is ridiculously small. I think that SA makes a crank that will work, but be prepared for people to point and laugh. I'd rebuild the wheel with a SA 5 speed if it was mine.