I'm trying to figure out my rim size for the future. Obviously the 16 1/2 are going into the garbage... They look very close to the drums and I'm not sure what the chevy disc backing plates will allow?.. it looks like if I go 15 in and want 35 12.5 tires I need at least 10 wide rims... I have no idea what offset I'll need to have or if I can even run 15s...??..