nah, the spindle would fit fine, it's the arms possibly not clearing the chainstays tha tis the bigger problem. considering his bb is a 68mm, and most road are also 68mm, that part is at least a non-issue.

shouldn't have any trouble with the chainring tabs, either. it's the arms that may or may not be the problem.

using a road crank on a mtb is a solution looking for a problem that dosn't exist, unless you just feel like running some odd gearing combos.