the tires do NOT run big. with 5 pounds of air they are 27" tall. with bout 15 lbs in them, they are bout 28" tall. everyone claims they are 28.5" + with only 5lbs in them. i guess if u put bout 20lbs in them and leave them in the sun in the middle of the summer for a couple days then they might stretch to were u can run only 5 lbs and still be 28.5" tall. i have the lift and i had to do minor trimmin on the back. with no lift, u may not have to do any trimming, since the lift brings the back tires forward jsut a lil bit. the tires are gonna hit the front fender bracket when turning hard though. they are really good tires though.