I agree with Doc Fiberglass. I had a set of 33 X 18.5 X 15 M/T's on my truck. Changed to 28 X 11.5 X 15 Hoosiers and picked up .3 in the 1/8 mile. Didn't have a traction problem with either and 60 ft. wasn't that much different but sure picked up the last 1300' with the smaller tire.