i know its wrong but my blazer still has a 1/2 ton front end and i have some 39 in tall ag tires on a 14 in wide rim. the center is cut out and iam going to weld a new center in it i need to know what back spaceing i need . igot mabe 5 in. of lift. i ran these tires last winter and this past summer on a set of rims from a friend and he sold them to someone else and i forgot to measure the backspaceing. can anyone help me. thanks the back spaceing ? is for the front of the blazer i aready got the back done.