okay so cruising to kerrville to move into my dorm and it turns out my speedomete is off.....BIG TIME!! by like 9 mph and i know its because of the hypertech tuner and what i set my tire size too, i put it at 28.5 bc i have 285 tires but it didnt work right, so what is the actual diameter of the tires and rims i have? the info is in my sig, so any help would obviously be helpful!!!

thanks
zach