Just bought a 07.5 NBS w/ 20" wheels and 275/60's. Speedo is way off. What is easiest & cheapest way to fix. Looking at used edge w/ attitude units. Do these correct this? Also I only have 75k mi. and do not want to void my warranty. Thanks

Edge module systems do not correct the cluster speedometer. Only way to correct is with a tuner to rewrite the ECM programming to correct. So if warranty is a concern I say get a GPS and use it for your speed. I do not know if the Edge module has a tire adjustment that will show the speed you would really be going. But that will only be on the Edge display. Again will not correct speedometer.

Brian

Brian

I have the Edge Evolution CS and have the correct tire height entered into the unit. When running a program other than STOCK, the speedometer shows the same speed as the Edge does. When you are programming the truck for any of the tunes, even if you specify the stock tune, the Edge will ask you if you want a custom tune. You must answer YES, and then only change the tire size in the following screen, then the speedometer will read correctly. Even the stock program with tire size changes made will display a "C" as a custom program.

BTW, I would entertain an offer of $400 for my Edge Evolution CS so I can upgrade to the Race version.

Yes on the Edge programmers the speedometer will be corrected. With Edge module systems there is no writing to the ECM so no correction to the speedometer.

Brian

I gotta believe there is a way to do this without voiding my warranty. I know dealers sell them new with lifts and oversized tires. I wuld think it could be a liabilty if they had speedos off this much. No? Thanks guys.

As to what tire size changes that a GM Tech II can offer has always been a confusion. Usually the only sizes is what tire sizes that were offered for that class is what was available. one can by a tuner that only alters tire size but again it rewrites the ECM tuning.

Brian