I'm currently looking for my first DH bike, but I'm not sure what size I am. I'm just about 6 feet tall and like a longer bike. I'm currently loving the feel of my size long Banshee Rampant with a 590 mm toptube, and I've noticed most medium DH bikes are a bit longer than this, by 7mm, so It's the length I'm looking for. BUT I've been told the toptube does not really give you the length of the bike. I don't want my DH bike to be shorter then my small travel bike, so how do I know what I'm looking for?