I was riding rather close to cross chaining almost all the time in the big ring, 53T. so with all the success of the compacts i thought I would just buy a 50T 130 bcd ring and slap it on there and adjust the hieght of the derailer. well it shifts great and i really like the 50T on there, i can ride more in the middle of the cogs. as it turns out it was a chainring from a triple, 50T,40T,32T... or something like that and it makes a noise as i ride. it is not the derailer rubing it sounds like dirt in the chain kind of, but only in the 50T not the 39T. it is a 10 speed chain maybe the ring is to wide... i really can not guess on this one. does anyone have any suggestions?