speedo re-calibrateon '05

OldManx · January 1, 2005

Does anyone know of a place that can re-calibrate the speedo on my '05 2500HD 4X4...Have added 285/75 tires and speedo is off about 4 mph. I am in Orange County, Calif. Thanks for any help you can provide...................

Dealer says that they have NO softwear for the '05's.....

GM-Tech · January 1, 2005

Dealer says that they have NO softwear for the '05's.....

I think they just don't want to deal with it because we do have programming info for 2005's. On the other hand, we can only recalibrate for tire sizes that the vehicle could have possibly been equipped with. We don't have the option to just enter any old tire size.

They *MIGHT* be able to get a VCI number for that tire size, but I suspect they will only be able to program for approved tire sizes. Don't know if that's one of them.

white8.1 · January 2, 2005

I have a 2004 and went from 245's to Lt285-75 Michelins. I talked to my dealer last week. They charge $84. They also told me that jumping up two sizes would not affect the anti lock brakes.

GM-Tech · January 2, 2005

I have a 2004 and went from 245's to Lt285-75 Michelins. I talked to my dealer last week. They charge $84. They also told me that jumping up two sizes would not affect the anti lock brakes.

Anti-lock brakes need to be reprogrammed too. Actually, it's just a matter of going into ABS > special functions with a Tech 2 and picking the appropriate tire size. Whether or not the size you have will be listed is another story.

As for your dealer... it's no problem if LT285/75's were an option for your truck.

Ag Teacher · January 3, 2005

I bought and '05 and had 285s put on the day I got it. I took it back to the dealer (within 3 hours of purchase) and they reprogramed it to 265s. That is the biggest tire their computer would go to but it's still pretty close.

They didn't charge and it was in and out of the shop in five minutes.