This seems like a good thread to explain my current situation and plans. My wife has an 1991(?) Trek aluminum frame road bike that I'm pretty sure is using a 126mm OLD hub, as measured with a crappy, plastic Fisher Scientific ruler. A few years back, I had our LBS lace up a new rear wheel with a HG freehub body for this bike, but I'm not sure if it will take more than 7 gears. I would like to upgrade this bike to use a 9 (or maybe 10) speed cassette, to allow a wider gear range. I did this exact thing to my old road bike, but that was a steel frame that I could cold-set. My plans for the Al frame bike at the moment:
- measure the rear dropouts and OLD using digital calipers that should have arrived today and confirm the 126 mm measurement
- attempt to fit a 9-speed cassette on the freehub body (cassette should arrive next week)
- if the cassette fits, move on to upgrading the derailleurs & cranks to modern 105 level equipment
- if the cassette does not fit:
- order a new freehub body that will accept an 8/9/10 speed cassette
- adjust the spacers on the rear axle to give adequate space for the new cassette (there is a large spacer on the left side of the axle; I'm pretty sure I will need only a few mm moved from the left side to the right side)
- assemble the wheel and adjust the dish to re-center the rim in the bike frame
The biggest potential issue I can see at the moment is that according to miamijim's work, 16-18 mm of dish on the right side of the back wheel is "normal", and anything outside that range should be avoided. I think my plans will require dishing to less than 16 mm on the right side, but I also cannot find any credible sources that show this will be an issue. There is a lot of speculation and lots of well-reasoned hypotheses out there, but I can't find anything that shows either a lab or real-world test that is relevant. In fact, plenty of 10+ speed wheels seem to be built with much less than 16 mm of right-side dish.
What do you people think? Will it work?