Actually thankyou both the answers have helped, I am still wondering if the increased overall height of the tires will knock down the final drive for lack of a better term of the 4.30 gears as I don`t need the additional payload they give, and don`t want the high rpm`s they cause at highway speeds, but at the same time I am worried that the same increase in tire size will drop the ratio too low in an F-350 as they have 3.73s if I am not mistaken.