I'm thinking of going from 17 to 18 inch wheels and was curious if there is anything I will have to do to make sure the speedometer stays accurate. I'm guessing it will all be taken care of automatically, but just curious. Also, will I be able to still use the TPMS after the new wheels/tires are installed?

 

is there a noticeable difference between 17s and 18s? I've been thinking about doing the same..

 

It will depend if you are increasing your overall tire height. I went with 295/45-18 in the rears so the height is taller and required a recalibration via the SCT.

 

The steering gear, shock, struts and springs need to be swapped for a "true" 18" pkg.

 

What exactly is a "True 18" package"???? i have 18's from the factory on my GT and the suspension is identical to the 17" suspension.....

 

Care to elaborate?

 

...lol...

 

I think the biggest difference on a car with 17s from the factory versus a car with 18s from the factory is the steering stop.

I have an 05 v6 that came with 16x7s from the factory, and I'm now running 18x9s. I have not noticed any problems.

I would recommend upgrading shocks/struts, but I usually only emphasize that when lowering the car.

Oh, and according to tire calculators, the overall diameter of my 255/45R18 tire is about 1/2" taller than the 235/55R17s, which would techinically call for a recalibration. I've been running it without recalibrating, so it isn't THAT big of a deal, but i'll probably reprogram it shortly.

 

No, 255/45/18 is slightly (negligibly) shorter than 235/55/17

 

What do we have here? a Ford dealership service manager?

There is no such thing as a "true 18inch package". Don't drink that Koolaid.