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Speedo calibration

2K views 10 replies 6 participants last post by  NCHornet 
#1 ·
I know they are only 33 in tires but any idea of how much they through off the speedo. Also would the speedo being off also make my odometer wrong too? Just curious about this for oil changes. Didn't know how far off it....
 
#4 ·
Anyone nearby that has AE? They could recalibrate the speedo for you. Or you could go to Ford to have it adjusted. But for 1 mile off, I probably wouldn't worry about it...
 
#6 ·
If your stock tires are 265/75R16 your speedometer should read about 57.5 when you are actually going 60mph. Your odometer will also be off by the same amount. Say for every 5000 miles you travel your odometer will only register about 4788 miles.
 
#8 ·
You can find "calculators" online that will do the math for you, but you can also just calculate the circumference difference. 35s changed mine 7%. I would just add 7% to the miles driven when calculating mpg. I recently discovered that my AE would calibrate the speedo and now it it dead on!



 
#10 ·
AutoEnginuity Scanner (Scan Tool)
 
#11 ·
AE can run many diagnostic tests that only Ford could do before. Cyl cont test, GP test, Injector buzz test, etc..... I will also monitor and live data log over 300 sensors on the 7.3. It is the best $350 or so you can spend on your truck besides a Custom Tune!!
ITP is who I recommend to purchase it from.
 
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