Originally Posted by
ramzilla
I've been using Deore M591 RD's on all my old 7 speed bikes. It's listed for 9 speed drivetrains but, works fine as long as you're using a Shimano SIS or STI 7 speed shifter. And, you can usually find them for $25 to $30 on ebay.
This Derailleur is listed for 7-8 so that should not be an issue.