I have an older gas-pipe road bike that may need a bottom bracket - the chainrings keep dropping the chain even without any sort of pedaling - even if it's not broken, the pedals themselves sound as though they're about to snap off. So I was wondering if it was alright if I could source a cheap MTB crank and/or bottom bracket and use it as a replacement. I don't want to buy a potentially expensive road crankset and chainrings and see them go to waste.
Would there prove to be any difficulties? I plan to run this as a single-speed with as little cost as possible; I've been treating it as one every since I gave up on making the front and rear dérailleur work.
With that said, what other parts can I interchange between the MTB and road bikes? I know that Surly equips the LHT with a XT RD and I've heard vague rumors about interchangeable road parts with MTB shifters or something like that.
This isn't my primary bike, in case you're wondering. This is just a summer project to do in my spare time.
Thanks for your help!