so i am looking to get new rims, i want the ion alloy style 174 but i don't know what amount of backspacing or offset is needed. i have 315/75/16s on my truck now. i just want the tires to stick out like maybe 2 more inches or so than what they are currently on the stock rims. if anybody could help me out it would be greatly appreciated. i am getting underway in the coast guard soon so i don't have to much time to research this on my own time. thanks.