I have a 9" front rim with a 30 offset. I don't know why anyone would want more but I think a 9 1/2" would fit. The problem is the tire size more than the rim size. A 245 fit with minor fender liner rubbing and now I'm on 255's on the front. I got minor cutting under maximum braking on the outside of the tire so I rolled the front fenders and now all is good in my world. On the rear I have 10" rims 25 offset and a wider rim will fit, I believe, but again it's the tire. Since I lowered my car everything rubbed. 255's, 265's, 275's and 285's. I used a heat gun, a brass hammer and fixed that problem. Most important is the offset. Get that right and your life will be easier.

Les