Originally Posted by
kroozer
Yeah, but they even say that the MTB's are for off-road roding. I'd figure that for roads and streets you'd want something more along the lines of road bike sizing, but the MTB geometry seems very different and not really comparable.
Its because MTBs aren't intended for road riding. While they certainly can be used, its not their intention.
I would stick pretty close to recommendations. MTB frames are supposed to be smaller. I normally ride a 57cm road bike, but I rode a 19.5" Trek 820 for a while and it was plenty comfortable. Expect to have a lot of seat post showing.