[71sierragrande]

Need more info to get specific. What is your wheel width? By big do you mean tall? Are you at stock height? I have a 265/75/15 at 1/2 ton stock height with room to spare. The first number is width of the tire, and is 24.5 per inch(thats not tread width, but total width). The middle number is percentage of the width on each sidewall. So a 265/75/15 would be approx. 10.8 inches wide. 10.8 x .75=8 inch sidewall. 8 x 2=16 inches for top and bottom sidewalls. 16 inches + 15 inch wheel diameter=31 inch tall tire. (its actually closer to 30 inches, I believe) Keep in mind that total width is about 2.5 to 3 inches wider than tread width, so I have 8 inches of tread width on an 8 inch wheel. As I said, there is room to spare at stock height, so you could go bigger