Hey Mitch, On that truck I am running 15x10 with 4 1/2in backspace with 275/60/15 tires I hope the bed will work out alright. On the truck I just gave my son I am running the same but with 4 1/4in backspacing it has a fleetside bed on it and they don't stick out and on the inside they still have a 1/2in on each side before they would rub.
