Originally Posted by
ftwelder
Since some point in time all derailleurs have been manufactured to fit one of two hanger configurations. The short road hanger and a longer touring/MTB hanger. Those are alike except the distance between hole centers. Not every one pics one or the other, some find something between. I hope this helps.
So, if i'm reading this right, i measure from the center of where the axle would be to the center of where the RD bolt goes?
-rob