mile markers and my odometer

[dieselade]

2018 silverado came with 255/75/17 tires.  I had walmart put on 275/75/17`s goodyear wranglers.  I am .2 miles short at each mile marker. Walmart being careful said the new tires were within their specifications for the truck. Is the .2 short miles the result of the mile change.  What does this do to the  hand calc mpg figuring?

[dieselade]

I meant to say is the .2 short miles the result of the tire change.

[mikeyk101]

This may help

 

 

[newdude]

1 hour ago, dieselade said:

2018 silverado came with 255/75/17 tires.  I had walmart put on 275/75/17`s goodyear wranglers.  I am .2 miles short at each mile marker. Walmart being careful said the new tires were within their specifications for the truck. Is the .2 short miles the result of the mile change.  What does this do to the  hand calc mpg figuring?

 

 

Are you sure about that size that was on the truck?  Stock 17s are 255/70R17, next size up is 265/70R17.  Take a look at the sticker in your door jamb for sure to see the original equipped size.

 

If its 255/70R17, you are off a good bit.  You need something like this: GM Flashcal For Truck | Superchips  to re-calibrate the truck's programmed tire size.  

 

[dieselade]

yes,,,,70 series

[CamGTP]

I love short replies like that, makes threads fun.

 

But atleast you know your answer now. Buy that device to re-calibrate your speedometer and you are good to go.