Well I'm a new summit owner. Today I found a mountain bike course that is all dirt which has a lot of nice jumps, and just an overall great area to drive in as opposed to the park that I was going to. I did notice on the loose dirt though that I'm loosing a lot of traction on the stock tires. I can't get the truck nearly as fast as I can with the grass. Could someone recommend some dirt specific tires I could switch over to.