recalibrating speedometer on a new GT

[Greco]

I just bought a new '06 GT with Auto tranny and the dealer is installing new 20" wheels on Monday. When I asked them whether they would recalibrate the speedometer, they said that it wasn't necessary!? I would think it should be done? Can you provide some help on that?

[2001GTPEWTER]

I think that would only matter if the car was under lease, even then the dealership would only go by whats on the odometer at turn-in date. With the new Mustangs I can't see a bigger wheel making that much of a difference in mileage, although it could.

[Jeff Chambers]

Depends on the overall height of the tire. Are the 20" a bigger overall diameter? There is a certain amount of N/V that the computer will learn. Your other option if the dealer won't do it is to get a handheld tuner like the SCT Xcal2 and adjust it via the tune.

[P.C.]

Someone put Carol shelby 20'S on at my dealer and it did need the recal. And yes they can do it at a dealer.I would go to a different ford dealer!Tuners are good for mods to rear gears firmer auto shifts.Adjusting fan temp turn temp.and more power!
I have a superchips tuner.It works great.

[Greco]

Originally Posted by Jeff Chambers

Depends on the overall height of the tire. Are the 20" a bigger overall diameter? There is a certain amount of N/V that the computer will learn. Your other option if the dealer won't do it is to get a handheld tuner like the SCT Xcal2 and adjust it via the tune.

I'm a newbie on this stuff, but they're replacing the 17" factory wheels. I don't know what the overall diameter of the new wheels will be, but I was assuming they're bigger. They're 20x8.5 rims and I don't know the details of the tire they're putting on there. I need to find out. What does "N/V" mean? Is the handheld cabibrator easy to use? Where exactly does it plug in? Thanks, in advance.