Actually, if you watch Fuel TV, Travis Pastrana (sp?) teaches random people how to backflip on a dirtbike, some people have never even ridden a dirtbike before and there doing backflips over 18 feet gaps and such. He sometimes starts them out on BMX bikes or Mini-PW-50's and slowly progresses them upward. This makes me think that it's really a matter of if you got it or not on backflips. It's really just knowing the momentum of the flip itself, if you know it, it's probably not as hard as it looks. I don't have anything big enough to try it on, mostly vert ramps and a few small kickers at my house I rather not break my neck trying. But when I go to 688 Skatepark I'll try it a few times into there foam pit. It's probably not as hard as it seems honestly.