Can i fit 30 inch tires on a stock 200 Gmc Jimmy?

Answer 1

Sure. 30x9.50R15LT's will fit just fine.

The question is, why?

Answer 2

I am going to assume you mean 30" tall tires, and not tires designed for 30" rims. If I am correct in assuming, and if your Jimmy is a 4x4, then yes 30" tires will fit, but you may need to trim the fenders slightly to keep them from rubbing. We fit 30" tires on an 86 Ranger, but had to trim the fenders down at the lower corners to keep them from rubbing during severe chassis flex off-road at full turning lock. The easiest way to check is to mount one tire on a side at a time, then turn the wheel all the way left, then have someone bounce on the front bumper so you can visually check if the tire is coming too close to the fender. Then repeat by turning the wheel all the way to the right. Trim as necessary, also watching to make sure the tire does not touch the frame or flexible brake lines. Be aware that a tire this size will change your final drive ratio which will make your speedometer off slightly. If your vehicle came with anti-lock brakes, they might also be affected. They can also cause premature wheel bearing wear due to the increased weight and stresses placed upon them by the larger tires.