Speed recalibration

[jsumner83]

I have a 2017 Sierra 1500 5.3 4x4. I just picked up the truck today after getting 4.56 gears installed. I noticed my speed on the dash is about 15mph faster than my actual speed, according to the speed app I was using. How do I get this recalibrated? 

 

Edited February 20, 2024 by jsumner83

[rav3]

YouTube has several videos on this.

[steelerdude15]

If you know someone with HP tuners, they can recalibrate it for you without having to purchase credits.

[CamGTP]

If said person has never tuned is truck before, they must purchase credits to tune it.

 

HP Tuners is never free to change tire size on GM vehicles.

[steelerdude15]

16 hours ago, CamGTP said:

If said person has never tuned is truck before, they must purchase credits to tune it.

 

HP Tuners is never free to change tire size on GM vehicles.

My bad. I though you could.

[MikeBMW]

Yep, gear changes will need a professional tuner application.
I do have "professional" tuner devices such as the FlashPaq (which is very good, IMO - it's a Holley branded tuner) which mainly correct for tire size.
I could be mistaken, however, as I've never performed a gear ratio change.
My Autel MaxiSys can, also correct for tire sizes but I bought that after I bought the FlashPaq. Not sure about gear ratio changes (see above.)
 

Edited February 27, 2024 by MikeBMW