Originally Posted by
rentilrebo
I am upgrading my DIY road bike with new Shimano parts when I can and the next part I'm looking at is a new crankset. My question is can I use any crankset on my road bike as long as it's triple? Can I use a mountain bike crankset on a road bike?
Yes, if other factors are matched, but there are complications.
You'll need a matching BB compatible with your crankset. You'll want to match the number of speeds closely because it affects chainring separation, so, for example a 10s chain might snag between the rings when shifting on an 8s mtn crankset. Then you'll definitely want a mtn front derailleur, since the typical road derailleur cage won't go low to clear the chain on the granny. That means that if you have index front shifting, you have to make sure the pull, or cable response ratio is the same (usually is if you stay within the same brand) and that the left shifter has 3 positions. Lastly, the RD has to have enough chain take up capacity for the wider spacing of your new chainrings.
Now if this is part of a long term conversion, you can start with the crankset, and maybe BB, but not using the granny, until other parts are changed to make it fully compatible.