I have a 2006 f-150 fx4 i just put 20" wheels and some open country togo mt tires size is 33x12.50xr20 i can't for the life of me figure out the MM circomfrence that edge is asking for I'm horrible at math please help me !

 

The math is simple: 33 x pi x 25.4 = circumference without weight on the tires.

Multiply that result by 0.97 to account for the "squish" caused by weight which will give you a good starting point. For your tires, start with a value of 2554mm, and make adjustments from there.

Make sure your Gear Ratio is correct whenever you open the custom options menu! It might need to be changed.

- Jack

 

Fine tune it till the Edge speed (not the speedometer) agrees with a GPS.

 

Thanks, I should have said that myself! These old brain cells just keep drifting off....

- Jack