A stock rim is a 15x8 right? I have seen really wide ones on one, but it looks like a donut. You can get some pizza cutter 38x9.5 or something, but that would look funny too. I dont know if the tire coming off would be a problem, but it seems like it could be. I would say the widest you should go is 12.50. the height is up to you.
90K5