I have a Raleigh/Campy SR with relatively short chainstays (41.5), 52/42 in front and 13-26 Suntour Ultra-7 on the rear. The rear derailler shifts just fine with all that; no problems getting onto the 26 at all, no twist teeth. My derailler is one with the black, and silver script "Campagnolo" logo. I happen to prefer primitive. When riding the Trek MTB I bought for my son, with Shimano (La-Z-boy) index shifters/deraillers that change silently when you just wish for it, I have to laugh to myself: "you call that a shift?"