I was told 18x10 at the least by "American's Tire" but i do know quite a few fella's are running this set up. I guess i just want to know if the tread issue is true at this point. Are the stock pro4x wheels 18x8 ?I'm sure the tire manufacturer will say that it should be mounted on at least a 8 or 8.5" rim but there are lot of guys running 325/65 and 35/12.5's on stock rims with no issues. The one thing that I have heard is possible is the tires wearing funny but like I said there are lots of guys with that setup and no issues.