Reprogramming tire size

[JonnyAWD]

Does anyone know if the dealer can reset tire size or revs per mile on the stock computer ? My dealer won't give a answer..

[LiftedAWDAstro]

I am sure they can but I have been told by the dealers before it was a liability issue as the M/L vans never came with larger tires. I offered them $100 cash once and was still told no!

There are options though. You can buy a programmer like a Jet Performance or Hypertech programmer or a Jet SCU (speed control unit) 2000.

[MountainManJoe]

I was told by the dealer that the computer could only be programmed for preset OEM gear ratios and tire sizes.

[97CargoCrawler]

I have the older GM TECH II dealership programmer and it does allow you to enter in the tire sizes for reprogramming.

I think you may be better off like Lifted said and get a reasonably priced programmer. Then you can mess with all sorts of stuff (shift points, etc)

[JonnyAWD]

What seems to be the best programmer ?

[97CargoCrawler]

I have the JET DST (Dynamic Spectrum Tuner). I wouldn't say it's the best, but it did what I wanted it to do. I reprogrammed my diff ratio, tire size and a few performance parameters. You can reprogram just about all of the LUT's (look up tables) that the computer uses to control the vehicle. It is a complete tuning programmer....i.e. you can seriously tweak your ride and seriously mess it up if you don't know what you're doing.

It requires a laptop to run the device and it disconnects after programming. It is not an "on the fly" unit with an LCD display like many are. Those types might be better suited to those who tow and change tire sizes from season to season.

I think "best" is subjective since it depends on what you want to do and how much you want to spend. The JET DST is about $400.