well I got 10.5 rears,so from what ive seen they are good up until 315 (maybe more,im not sure). But due to the fact that they only make tires so wide in a 17'' rim,I went with a 285.
Oy . . . 285 on a 10.5" rim might look a little narrow frankly. :??: Like I said, if you look at my pictures I have 295s on 9.5" rims. It's been my experience that usually folks run 305+ on 10.5" rims. When you get them mounted, post some pictures, I'd be curious to see how it looks?