I want to use my older 7 speed wheel (126mm) with my newer 130mm frame.
I am not worried (at least yet) about shifting. I am under the impression that I can use my 9 speed chain and derailer with the 7 speed cassette using friction mode - Correct?
I understand that my 126mm hub has a long enough axle to fit my 130mm frame - Correct?
I need to place some washers on the axel to get it to fit the frame. Do I place the washers on one side of the hub or both?
Do I need to re-dish the wheel or can I avoid re-dishing by using the axles correctly?
Am I missing anything else?
(I have not been able to find the exact answers to these questions on the web, including Sheldon Brown’s helpful site.)
Yes, the 9-speed chain should run on the 7-speed cassette but a 7/8-speed chain will likely work better.
Yes, the axle is probably long enough. It’s likely 137mm and that will give you 3.5mm per side.
If the wheel is dishable, I’d place all 4mm of spacers on the non-drive side and redish. If the wheel is non-dishable (e.g. disk or trispoke), place 2mm of spacers on each side and adjust rear derailer stops.
Years ago I did something similar. I took a 126mm road hub and spaced it out to 130mm and built an MTB wheel. I put all the extra spacers on the non-drive side to get a stronger wheel (less dish).
9 speed chain and derailer with the 7 speed cassette using friction mode - YES
126mm hub has a long enough axle to fit my 130mm frame-USUALLY, unless your hub has an atypically short axle.
I need to place some washers on the axel to get it to fit the frame.–IF you have a steel frame, then no washers are necessary, just squeeze it down with the hub QR. Ti could probably be done without washers also. If you have an aluminum or carbon frame, probably should use washers. If the wheel is going to be exclusively used in the 130mm frame, then I would use the washers, regardless of frame material.
Do I place the washers on one side of the hub or both?–Either can work. If you put 2mm on each side, then no redishing of the wheel is necessary. If you put 4mm on the non-driveside and redish, then the wheel will end up stronger. Personally, I would put 2mm on each end and be done with it. I have done this and put over 10K miles on an old 126mm wheel with 2mm washer on each end run in a 130mm frame with no problems. Technically the 4mm on one side with a redish is a better solution.
Do I need to re-dish the wheel or can I avoid re-dishing by using the axles correctly-SEE ABOVE