[Brian Ha]

Okay, so the reason we chose a bottom rotational wheels and then just a bar over top was for back spin. Adjusting speed and bar location give more spin vs more distance. Back spin is definately wat u want.

Now some reasoning behind why I think u shouldnt have a wheel unpowered on top, wheels have much more friction over a bar. The bar is used for back spin, thats why it works. The wheels that r underneath it are use for propulsion.

Thats wat I think atleast.