I want to buy new rims for new tires I am placing on this hot rod truck. This truck was setup with a narrowed Ford 9" rear end. The truck currently has Hoosier 29 x 12.5 x 15 racing slicks. I am replacing this size tire with a 275 x 60 x 15 which is 2 inches more narrow in width. The new rims will be 15 x 10. I need to figure out what the offset and back space needs to be to get the tires to sit correctly on this truck. Ford 5 x 114.3 (4.5") lugs. How do I figure it out?