For those that ride road and MTB, do you have separate helmets for each or do you use the same one for both? I've always used the same helmet for both and remove the visor for road. I found a couple of cracks in my current helmet so I'm shopping around for a new one and I'm not seeing much that I like and would work for both aesthetically (yes, I'm a slave to fashion :?. If you use one helmet for both, what's your favorite? A separate question, what's with the MTB helmets coming so far down the back of the head? I'm trying to envision the situation of hitting my head on the lower back part and I just don't see the circumstances where that extra length would make a difference.