I want to set up a 10 speed Campy drive train to handle a 12-25 (coastal riding) and a 13-29 (mountain riding) rear cassette. I want to use a medium cage rear derailleur which will handle both cassettes, but all I have is a 9-speed Centaur medium cage from after 2001 (after Campy changed the cable pull length specification). Will the 9-speed derailleur handle the 10 speed shifting requirements properly? I do have a long cage Chorus 10-speed rear derailleur and I was also wondering if there were any downsides to running a long cage derailleur with a 12-25 cassette? My intention is simply to change out the cassette and the chain when moving from the 12-25 to the 13-29. Thanks for any info!!!
Also one more question, has anyone out there ever successfully run a 10-speed Campy short cage rear derailleur with a 13-29 cassette?