Probably a 19x8.5 then. I'd go with a 255 or 265 on that width rim. If you want stupid fat tires you're going to need to go with a different set of rims too.
2000 Mustang GT Steeda #0048 34k miles. 99 Cobra 4V swapped, FTBR IRS swapped, exhaust, tuned by James Gordon.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.