Originally Posted by Retro Grouch
9-speed bikes use a slightly narrower chain than 8-speed bikes. When 9-speed bikes came out, Shimano carefully labeled it's front derailleurs for 9-speed use. I assume that they must have a slightly narrower derailleur cage.
If it was my bike, I'd just slap on whatever 9-speed derailleur matched my budget. If I could get the shifting to meet my standards using an 8-speed chain, fine. If I got more derailleur cage rub than I wanted to live with, I'd change to a narrower, 9-speed chain.
Thanks.
Can you just switch out an 8-speed chain with a 9-speed chain (assuming, of course, that the length is adjusted) without any other effects on the drive train (e.g., wearing out the cassette faster, etc.)? If so, why do they bother making 8-speed chains and 9-speed chains instead of just a universal chain?