On Tue, 15 Apr 2008 23:01:11 GMT, Jeff Welch wrote:

I have an old huffy 3-speed, my best guess is that it is from the
1970's. I'm just learning how to maintain and repair my own bike, and
was wondering if it is possible to convert the current Shimano 3-speed
hub to one of their new Nexus 7-speed hubs. Where would I start to
figure out if it's even possible? (Tire size, frame fork, something
else?)

A point to consider is that the Nexus hubs have a control-cable arrangement
that runs inside the chainstay, while the SA hubs have the control-cable
running through the axle nut.

This means that you may need an anti-rotation washer for the Nexus
different than what may be supplied, in order to get the control-cable to
run in the direction you wish. These washers have varying degrees of
offset between the axle flats and the dropout tangs; I think they are
available separately, but you may have to look hard.