Offset on ROTA's seems to be around +48 normally, which is fine. On 18x8 wheels, you can run 235/40/18 without any problems, even 245/40/18 will work but is close to the "fender rolling" size....this is the exact setup I have on my ROTA's with tires (which are for sale by the way if you're interested in the ROTA P1 in Hyperblack).