So I've got an old 7 speed rear wheel with a crapped out RX100 freewheel (ok, I can't ever remember which one is a freehub and which is a freewheel - but it's the modern sort, just for 7 speed, circa 1992).
If it doesn't prove to be too difficult, I'd like to rebuild it using whatever cheap and/or used parts I can get my hands on, to use as 9 speed - to have with a turbo trainer tyre just for trainer use.
My question - can I just replace the freewheel (freehub?) with a 9-speed one? Is the difference in width there what makes rear dropout spacing wider on modern bikes? Or will I have to re-dish the wheel?
If I'd have to re-dish the wheel, I figure I'm probably better off just picking up some old 9-speed hub from e-bay and replacing the whole hub. Wouldn't be a bad way to teach myself wheel building, I suppose, either.
Any other options?