Can dealership reprogram for oversize tires? shift points?

[Donnyb313]

Anyone know if the dealer can reprogram for oversize tires?

 

I don't really care about the speedometer being off, I'm more concerned with the shift points, I'm switching from a 32.5" diameter tire to a 34.5" and I'm wondering if it will mess with the shift points on the 8 speed? Possibly shift too early 

 

My local dealership said it can't be done, but they've been wrong several times before.. 

[tbarn]

They cannot.

[Sierra Dan]

Why pay a dealer even if they could do it vs your own programmer/tuner you can keep?

[Donnyb313]

I might be wrong but I don't think there's tuners out yet for the 19's 

[Leevon]

Correct, dealer cannot.  No aftermarket tuning yet that I know of.  For simple tire height change, Hypertech 730129 speedometer calibrator is what you need.  This will also help with your shifting.  I need to order one, if I beat you to it I'll let you know how it does!    730129730129

Edited March 27, 2019 by Leevon

[lt1z]

Dealer can only program factory files for your VIN. You will not be able to adjust for tires larger or smaller then stock until aftermarket tuning is available.

[Donnyb313]

2 hours ago, Leevon said:

Correct, dealer cannot.  No aftermarket tuning yet that I know of.  For simple tire height change, Hypertech 730129 speedometer calibrator is what you need.  This will also help with your shifting.  I need to order one, if I beat you to it I'll let you know how it does!    730129730129

Yeah let me know how it is once you buy one! Thanks! 

[Eds240z06]

[BillyDee]

On 3/27/2019 at 4:27 PM, Leevon said:

Correct, dealer cannot.  No aftermarket tuning yet that I know of.  For simple tire height change, Hypertech 730129 speedometer calibrator is what you need.  This will also help with your shifting.  I need to order one, if I beat you to it I'll let you know how it does!    730129730129

Anyone buy a unit yet?  I am considering one, mostly helping it helps with the shift points.

[lt1z]

Anyone buy a unit yet?  I am considering one, mostly helping it helps with the shift points.

All this does is correct the speedo. It has no effect on shift points

[BillyDee]

11 minutes ago, lt1z said:

All this does is correct the speedo. It has no effect on shift points

Boo.   Thank you, I will pass then.  I can remember that the speedo is off 5 MPH at 70 MPH  

That Hypertech React Off-Road may be a better investment for the extra $100 if it works as advertised.

 

http://hypertech.com/vehicle-results.aspx?AAIAID=510043

 

[BillyDee]

14 minutes ago, lt1z said:

All this does is correct the speedo. It has no effect on shift points

 

Oh... also... i saw a post where someone said they use "L" in the mountain situation to set a max gear.   I tried it this weekend and works well.   Thanks for that tip whoever it was!!

[BillyDee]

So i put that money towards a pedal commander and I am very happy with it.   It doesn't add any power, just changes the responsiveness of the throttle, but it sure feels like it has another 100 HP.   Sport mode is jumpy enough around town that the whole family noticed... they asked why i was driving so aggressively   

 

As interesting as the instant response to pushing the throttle... is that it downshifts when you give it a bit more gas... where without the commander the same amount of throttle would have kept it in the same gear and lugged.

 

Very noticeable upgrade vs just having the speedometer accurate