I believe 10 is the widest but I dont think you can run any tires wider than 275...you will probably need to remove the quads but if you want to run wider you will need to get minitubs
Running 15X10 Draglites with 6.5 B/S. Have Hoosier Quick Time Pro's 28X13.5X15. Fit with no quads, tailpipes rubbed, so i dumped the exhaust before the rear axle. I recommend getting a torch and a BFH (Big Flippin' Hammer) and get ready to heat and beat. After that, spraypaint the inner wheel wells and take it for a ride...if the paint smudges you have rubbing. I'd say on a 10" wheel you could go as big as 315's no problem using this method. The prefered rim is a 15X8 with 5.5 backspacing...that will let you keep your quads and no modification to your wheel wells. Any questions..ask away. Good Luck!