Largest tire recommended (by Discount) on stock wheels and no lift is 30x9.50-15. Every chart I've seen says with 4 1/2" lift the largest you can fit under is 31x10.50-15. Anything larger than that requires modification / more body or suspension lift. I'm still in the process of planning out my buildup, I'd -like- to get 33x10.50-15s under mine. We'll see.