SVT32VDOHC said:285's will be just fine. 315's will go onto a 9in wheel, but that is the max you can go.
Nobody said:According to BFG's specs, 9" isn't even within the range of rim widths to mount the tire on. The narrowest is 9.5". The section width of 11.4 is on a 10" measured rim. That means that the tire will be squeezed onto the 9" wheel, making it narrower.
The approved rim width range for BFG 315's is 10.5"-12.5".