Tire size adjustment

[ogre20012001]

Hello all.
I have a 2014 EL limited 4x4 3” lift I just put 35” (285/75r18) tires on it, and I’m looking to adjust the speedometer with forscan.
Does anyone know how to adjust for more than the standard options?

 

[Jchouston]

I just did mine on my 2017. Put 275/65r20 on which was not a standard option. I entered the circumference of the tire in the BCM module and it was still off, someone suggested taking off 5% and now speedo is dead on.