I have a custom tune on my truck and I was wondering about the revs per mile. I have 265/70/17's on my truck now and the revs per mile for them is 638 and the sct programmer will let me pick 635 or 640 ect. and I could leave it stock.

 

It's not possible to change that . . . it's an equation determined by the tire's circumference, not some adjustment . . . I feel like I'm missing something here.

 

I had the same problem. I tried both. You just have to see which one works best with the speedometer.

 

Ahhh trying to correct the speedo. Should've guessed that. I was missing something.