SteveCrowley

Can I use an older Campagnolo derailleur (6 or 7 speed) with a 9 speed cassette and 9 speed shifter?
Currently I am using a really old Shimano 600 5/6 speed derailleur with Shimano 7 speed, and it works perfectly fine, but I am wondering if anyone has done such an extreme jump as 6/7 derr. with 9 speed.

bluenote157

i was using a shimano 105 "6 speed" rear with 9speed sti.. no problem.
It's only when you start messing with 7400 series dura ace that it becomes a problem.

as far as campy is concerned, i really dont know.

desconhecido 

Probably not. Typically, any Shimano indexed derailleur will work with any Shimano indexed shifter so long as the shifter and the cassette match. That's because the Shimano derailleurs all move the same amount for a given amount of cable pull. The exception to this rule is that early model Dura Ace derailleurs didn't respond the same as other Shimano indexed derailleurs to an increment of cable travel. I don't know about six speed indexing for Campagnolo, but Campagnolo 7 speed and 8 speed derailleurs responded identically to cable pull. Early model 9-speed Campagnolo may as well, but I'm not sure. Later model Campagnolo 9-speed and 10-speed were different. So, if you you have a Campagnolo indexed 7 or 8-speed derailleur it might work with early 9-speed shifters and a 9-speed cassette, but won't with later 9-speed. Also, if the derailleur was not intended for an indexed system, you're probably screwed.

Go to this site for details on all this: https://www.ctc.org.uk/DesktopDefault.aspx?TabID=3946