On the dirt, the extra articulation provided by the Full Traction springs let our big Super Duty go places it couldn't go in stock trim. The 6 inches of lift also kept the body out of harm's way and helped improve the breakover angle of our super-long crew cab longbed. In addition, the ride could be described as plush. Our 37-inch BFGoodrich Mud Terrain KMs were about the limit for tire size and we experienced some minor rubbing. With some slight fender trimming they should be fine.