I want big. I've posted in other sections about the engineering on the big tires before.
I want to do a fat tire in the back but that could be too much. Because you want to be able to through that back end around. A fat tire will make the fronts go straight and not want to turn as well.
I still want at least 20 in in the back but a really wide tire.
What do you think of some of the new hub less wheels?