I'm thinking about ditching the MTB triple on my Bridgestone XO-4 and replacing it with a compact double. I'm running a 7 speed rear in friction mode. My question is, if I put on a crankset made to run 10 speeds, will I have to use a 10 speed chain, and if so, will that cause trouble with the 7 speed rear? Should I just leave well enough alone? It's definitely rideable as is, but there are times when the 42 x 12 high isn't enough, and I'm never on the granny ring.