I was wondering how the inner limit (small cog in the rear) is set using a Campagnolo Rally rear derailer? I am using it on a frame that is 126mm spaced and a 7 speed freewheel (13-32). The chain is getting hung up between the rear drop out and the small cog. Last Time I set his RD up, I had no problem using the exact same set up. What am I forgetting?