Originally Posted by
maddog34
explain how changing the chainline will increase the clearance between the outer ring and the crank arm.
I missed that it's rubbing on the crank arm. He didn't initially specify what he meant by "too far out". He also didn't initially say that he checked the chainline.
I guess I assumed he would have adjusted the FD for that crankset, but that was admittedly a bad assumption as well. Without pictures it's hard to know what's really going on. I wouldn't be so sure that the crankset and derailleur won't work, without seeing it. I have put road cranks on MTB frames with no issue, and without having to change the FD (or worse, bending things). But again, I always start with a good chainline and correct position of the derailleur.