The main reason I only put a 4" is because I do haul and I wanted the truck to be functional. I'm running 35" and that is as big as I want to go. My trailer has the sub-frame and the trailer still doesn't sit level with the 35's...but it's close. My trailer height is at 13' 4" so raising the trailer wouldn't make any since. Plus for hauling purposes the bigger the tire the worse the mileage. I lost 4 miles per gal going from 265'sfastcrazyhurt;1546613; said: