I'm just wondering if anyone else running large tires has problems with launching in 4wd. Mine bounces the tires off the ground alternating from one side to the other.. My 60' times are horrible now in 2wd.. My best last thurs was a 2.2..... I tried air pressure from 21 lbs to 30 lbs.. I'd like to get the truck in the 13's with my current combination.. If not I guess I'll have to break down and go with the quad box.. Any suggestions would be appreciated...