Replacing a rear Tiagra derrailure
I need to replace my rear Tigra derrailure which runs on a 9 speed Shimano cassette. I seem to be looking at a lot of 10 speed Tiagra derrailures, but can't seem to find a 9 speed one. My Giant SCR 2 is 8 years old now. Can I replace the Tiagra with a 10 speed, even though my Shimano cassette is a 9 speed? I ave a triple chain set. I also see that derrailures seem to be short or medium. Not sure which one I need. Any help would be appreciated.