I saw an Ebay listing for a Mirage 8-9-10 rear derailleur. I hadn't really thought about it, but is there any functional difference between the different Campy rear derailleurs ?? If you have 10 speed brifters & cassette, will a "9 speed" derailleur work ?
I want build a budget 10 speed Campy bike for my daughter, shopping for lightly used parts on Ebay, and wondering how picky I need to be.