Speedo Question with Bigger Tires

[rsrelram]

I have a 07 Sierra Classic CC 4X4 LBZ with stock 245/75/16 tires. I upgraded to 265/70/17 tires as I got a great deal on a set of wheels and tires. I plan on putting 285/75 tires on stock 16 wheels to run during winter. Is there a programmer that I can get to correct the speedo with the different tire sizes? I have been told that the ECM on this truck with the Allison will not allow this?? Is this true and if not, what programmers will allow me to make the change to correct speedo. Any and all information would be greatly appreciated.

Thanks

[DunesRunner08]

Most programmers I have seen will allow you to adjust for Tire Size... who gave you that information...

If you are not looking for a lot of power and just want some adjustability and a little bit of power, the Edge Evolution is a good route, mild power and all your gauges in one setup... but.... the PPE standard is probably the best canned tuner out there for the trucks....and then EFI is the best tuning period.... but you need a lot of know how to play with EFI....

i am sure one of the vendors on here will jump in to help you out with pricing shortly

[rsrelram]

I was told this by a service advisor from a GMC dealership. He said that his tech told him this.

[DunesRunner08]

well they were full of you know what.... dealers as well as some corporate owned accessory shops (different thread different time...soon) will feed you crap so you dont put a tuner on your truck

[BigOlDog]

just putting it out there i think my dealer told me that they would change my tire size for me (in the computer). also have heard that they can put it in tec 2 and the 95mph limit is not there in this setting. this comes from a friend who works at a dealer. have not asked if they would do it for me yet. soo take it how you'd like.... other members may know if this is true.