> I'm thinking of buying a speed sachs hub for my bike. does anyone happen to
> know the dropout width required for one of these?
The Sachs 7-speed hub has been replaced by the SRAM Spectro S7.
Sheldon Brown lists this as a 132-mm hub for the brakeless and drum
brake versions, and 130-mm for the coaster brake version:
Mr. Brown also offers a gearing calculator for both the older Sachs and
the newer SRAM internally geared hubs: