Hope somoene can answer this. I just put some 24's on my Tahoe to replace the stock 17's. I did some calculations and the difference is a 0.8" increase in OD. The guy at the wheel shop said that I wouldn't have to recalibrate my speedometer because the computer will automatically adjust for the increase in OD after a certain number of miles (New feature on some new models i guess). I have never heard of this, so I was wondering if anyone else knew. Or is this guy full of it. If he is full of it, would it be recommended to fix the speedometer or is the increase minor enough to leave it alone. Thanks.

 

Hi. I have not heard of that automatic fix either. I know I changed my OD size and it never adjusted it for me, 07 Tahoe as well...
You will need a programmer for your vehicle to adjust this size. I also do not think they would make it an option or build programmers with those features if it is automatic on our vehicles...

 

Tire size calibrations are programmed into the ECM/PCM andVCM, the computer does not use a fuzzy-logic (learn as you drive) method to recalibrate.

Many tire/wheel dealers are using similar statements as a cop-out response to get you off the property and shift your focus away from an issue that they are unable to address.

 

Hey thanks for the responses. It sounded like the guy was full of crap. Anyways, so are there places that can do this for me (Southern Cali. LA area) or do I have to sack up and spend on a programmer? Thanks guys.

 

Even dealers that are installing GM authorized lift kits and larger tires have to use the aftermarket programmers to get the correct settings.

 

Is there a specific programmer that is recomended?