What is the widest tire you can put on the rear of a stock 18X10.5 rim? And if a 315 is the widest who makes them? I know you can get a 315 on there but will a 335 fit or is that too wide and made for an 18X12 rim? I'm just looking for the widest tire I can put on the back of my Z06 to help plant these ponies on the ground. I really want a mickey thompson ET street but I think the largest they come in is 275/40/17's.