I have recently been building a bike and ran into a problem when I bought shifters. I installed Sram shifters (7 speed) and paired them with a dura ace derailleur. In doing some research I realized that some shifters are 2:1 ratio and others are 1:1. These same shifters would not work with my other bike. The Sram shifters would not work with my front derailleur -It threw the cage too far with each click. All is well for now, but my question is...How does one know if a derailleur isw a 2:1 or 1:1? Do any of you have access to a list of compatible shifters and derailliers. Does such a list exist? Thanks for any insight you can give.