I think I might have put the speedometer needle on just a hair off of what it should be. A few months back I bought a white face gauge overlay. I think I might have put the speedo needle on a bit wrong because my speed reads differently than my GPS. I did change wheels/tires since then, but the new od is only .2" bigger than stock. I played with my programmer and set the tire size to 31" and the speedo ran consistent with my GPS at any speed I chose. But if the information is incorrect it will mess with my odometer readings. Correct? Any help would be greatly appreciated. Thanx.

 

What size tires do you have? If they are 1/4" different or more than stock, I would use the HPP to calibrate the speedo. You said they are .2 bigger than stock, so I take it the stock tires were 30.8" or 31.2" in diameter and the new tires are 31", which is now your setting? www.4lo.com has several calculators on it, use the one about tires size and found out exactly the tire diameter and input that using the. The HPP will let you make 1/4" adjustments.
Jim