[hemi deep]

I was going to get my trucks computer adjusted for my new 33" tires. I checked my speed at 120k(via GPS), it's now only 3k off. Any stock wheeled 17" owners out there able to GPS on cruise at 120k?

 

[OldPoop55]

No but, I bought a Speedometer Calibrator from Hypertech when I upgrade my stock 2500 to 35 inch tires. Pretty easy to use and I am not mechanic. Took a couple test runs of adjusting tire sizes but, my speedometer matches my GPS.

If this helps any.

A helpful hint. This device marries itself to your truck. It cannot be used on more than one truck.

 

[ryan69]

Not sure, but after I put on my 33's I was 3kmh over just like you are.