Shimano 8 Speed to 9 Speed compatibility and parts

[IFRider]

Currently riding 8 speed XT on the mtn bike with pod shifters that are finally starting to get glitchy. I have long thought to pick up a pair of Paul's Thumbies for use with a pair of 8 speed bar end shifters I have from another project. Before I do that, I was looking at rear derailleurs to make sure I could find a something when needed. As I recall, the 8 speed was the same spacing as 9 speed. So figured a 9 speed derailleur would work. Conversely, I thought the 8 speed shifters (bar end and down tube) had an extra click that also works on 9 speed. Ideally, I would pick up a new 9 speed cassette with higher capacity (32 teeth), and be able to run the Paul's shifters with the 8 speed bar ends. Any thoughts are appreciated.

Warren

[josephr]

you're good...I run an XT 8-speed RD with 9-speed shifters on two bikes.

[moobikes]

You will not have a problem using any 8 or 9 speed RD with any of the shifters you have but the shifter and the cassette should match if you want to the shifting to index properly. 8 and 9 speed cassettes have different spacing between the cogs. It's close enough to work but you will get lousy index shifting.