Noob question-
I searched for the answer becuase I remember seeing it posted before but I couldn't find it.
What is the equation to obtain the adjusted mileage with larger tires?
If I remember correctly, if your tires are 5% larger in diameter, then you need to add 5% to your average MPG, right? Or do I have that switched?

Thanks!

 

You would add the dfference to your mileage. Not sure if that ends up being the same thing as adding it to the MPG's or not. Haven't thought through all that yet.

Calculator

 

Awesome! That's exactly what I was looking for. Thank you!

 

https://www.yotatech.com/~corey/portal/portal.htm

Scroll down to the tire/wheel calculator. Use the actual heights of your tires. You'll have to go to the manufacturers' websites to find out what the actual height of your old and new tires are. For instance I went from a 31" tire (30.7) to a 265/75r16(31.8). That is about 3% difference