i have no idea what the stock tire size was. it had 33's when i bought it. and its about 250 miles away from me right now, so i cant jsut go look at it. best i figure, its about 30% off. but i plan to just try and stay with the flow of traffic, best i can. im might make a little cheat sheet with some of the most common speed limits and what my speedo should say so i can stay within the limit.