Originally Posted by JackandJanet

But, with taller tires, you will be going faster (6% faster if that was the difference between the old tires and the new ones) than the speedometer says you are doing. If your local finest are zealous in ticketing speeders, than you will have to allow for that much error when you are driving.

- Jack

Originally Posted by glc

A tire shop is not equipped to do that. The Ford dealer may be able to do that for you, or you will need a programmer and tunes to do it yourself. With tunes, you can improve on some other things too. If it's not off far enough to bother you, you can just live with it. Reprogramming is not free.