Originally Posted by amish cyclist

Hi, I'm looking to replace a Shimano Sora derailleur with an older Dura Ace 6-speed derailleur I came across on eBay. I have a 7-cluser Dura Ace cassette, does anyone know of any compatibility issues? Sheldon Brown has a good article that I hope is correct, but I'm not certain what year the components were manufactured. Any experience or insight is appreciated.