If you have too much air in the tires, it will not have the best traction and the wheels slide easily.
I have the Sport 48" and it seems a little light in the rear and maybe not as much traction as I woud like, but it's ok. I did put too much air in the tires once and had more sliding.
I learned to change my driving style a little and reduced the sliding a good amount. If you get both wheels rolling then turn it will slide less than if you try to turn from a dead stop, for example.
I don't know if a different, more agressive tread pattern would help.