Will I need to calibrate my speedo?

[ARTTII]

My car is a 2007 GT Premium with IUP, 3.31 gears. All stock. Standard 17" silver bullitt painted wheels.

I just picked up a set of 18" polished bullitts. When I put them on will I have to recalibrate my speedo? And if so how can I go about doing that?

thanks

 

[Kilmar]

Yes, you will need to recalibrate. You can either bring it in to a shop to be reprogrammed or buy a handheld tuner like the SCT XCal II and get a tune with 18" wheels.

 

[kooldawg6]

If you went from the 235/55-17(27.2" tall:768 revs per mile)to the 235/50-18(27.1" tall:759 revs per mile)then you don't have to recalibrate.(tirerack.com info).
My SCT tuner gives you changes in incriments of 5. To me that would not be worth a tuner if you don't have/plan on getting one anytime soon.

 

[ARTTII]

Thanks I knew it had to be something electrical (i.e. no cable present) but I didn't know if there was a shortcut that I could use to reprogram it. Thanks for the info.

Also, good point about how close the final height of both wheel combos... I think I will leave well enough alone for the time being. No need for a tuner, yet!