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Discussion Starter #1
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
 

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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
The 285/70/17's.....The Tires have a Overall Diameter of....32.8in's
 

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You are sitting at 32.7 so I would enter in 32.50. Remember the faster you are going the more off you will be.

You beat me to it Mike.....hahaha
 

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Or just go the same speed as everyone else on the road till you get it fixed.. You can also take a tape measure from the ground to the top of the tire..
 

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yes 32.8 like they said the 3 digit number is NOT your diameter! it is the width of the tire
 

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yeah like they siad 285 is your width of tires in mm 75 means your sidewall is 75% of the 285mm which is really about 11.5inches just for further info :great:
 

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Discussion Starter #7
thanks guys for all the help just fixed it about an hour ago and its working i had been driving like that for nearly a month im extremely lucky i wasnt pulled over thanks again
 
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