Can I fit a modern internally geared hub on an old bike ? I have an old Hercules frame that I have no use for but don't want to get rid of - I am in need of a new "town" bike for running around on, however I need something practical with a nice gear range... I like projects and building things, so the thought of building up my old hercules into a useable everyday bike has crossed my mind :) But... is it possible ? 

I thought a Nexus or even Alfine speed hub would be perfect, however there would be a 135mm hub spacing required from such hubs, of which my frame is a lot smaller. Its a steel frame so I think I should be abled to modify / cold set the frame and increase the spacing to support a 135mm hub ... ? 

Is there anything else that I should take into consideration ? should I worry about the bottom bracket and crack spacing ? can I also upgrade the bottom bracket and crank to something more modern on such an old frame ? 

Thanks !!!! 

Jon
While you probably could cold set it, the Sturmey-Archer XRF-8 is available in a version with 120mm OLN dimension.

(And you almost certainly can fit a modern bottom bracket. Worst case, have the existing threads removed and fit a threadless bracket. Bottom bracket size guide.)