Hi, I built a bike from a Schwinn al.comp mtb and the conversion kit. It worked fine but the crankset was geared to low- 22/32/42. I replaced it with a Shamano 27/38/48 and now I can't get the derailleur to work. It appears to be on the wrong angle and the chain rubs either one place or the other. Do I need to use a different derailleur or what? I'm kind of new to all this and this is the first time I really did anything with a bike like this! Any ideas how I can get back on the road outside of going back to the old crankset?