Usually you can stretch certain sizes very close to the stock size tire onto a rim(wheel). This is the case for almost every rim. It is just user preference but there is usually a recommended sized for any given width. For my rear rim I have stretched a 275 onto a 10.5" wide rim, I can go wider to probably 295 and the tire won't be as stretched. I don't know off the top of my head what size tires would fit on the 8" wide stock rim. But if you call up a tire company or find certain websites online, they can give you the range of sizes available that will work.