grancuda

We are swapping our 2011 with 215/65/17 to 275/40/17. Do we need a new tune for the shift points and speedo correction?

hogasswild

If you already have a tuner I would request new tunes since you'll be 2.3" shorter.

6+6 Stang

or you can just make the changes in the handheld as I did on my '10 gt, that is the advantage of owning the tuner, tire size should not have anything to do with shift point, just need to change the area where says revolutions of the tires.

hogasswild

I did not know that, good to know for future reference!

Franchi

This. It's one of the parameters you can adjust yourself with the SCT.

D BERRY

If you already have an SCT tuner then all you have to do is change the revolutions of the tires to compensate? My tires and gears are not stock and my odometer is wracking up more miles than I'm actually running, speedo is 6 MPH off at 60. Guess I'll have to see if I can figure out how to do it now.

Dave

Nuke

+1 on making the tire RPM's change yourself with the handheld. No need to change shift points except when changing gears. But if you DO want to change the shift points, that WILL require a revised tune.