Hi - I need your help. I'm trying to build up a cannondale cad3. I got a rear wheel with a 8,9,10 hub. i had a bike shop put a 7 speed cassette on it with a spacer. Now the chain alignment is all off and the chain rubs against the front chainring in most gears. Do I try a different spacer on the 7 speed or just buy an 8 speed cassette?
I think you have to match the cassette to the shifter or you'll never get the rear shifting to work right.
I assume the shop put the spacer inside of the cassette. If you are getting a lot of chain rub against the inside of the front chainrings, you could try putting the spacer on the outside, under the locknut. That would move the whole cassette in one cog width which might give you better chain line. Just make sure that you check the limits and cable tension on the rear der.