This morning while exploring the TUPS programming with the Superchips Flashpaq; I discovered the factory or dealership had programmed the tire size at 30.75". My Wrangler Sport S originally was shipped with 255x75R17 (32.1") tires; so I it is unclear why the program setting wasn't around 32". I am sure this setting had an impact on the automatic transmission shift points and the speedometer readout.
Figuring the tires are worn.... I changed the tire size to 31.75". I will drive the Jeep for a few days to see what impact this change has on vehicle performance.
Anyone else find a problem with inaccuracies in factory programming?
32" tires are not actually 32" under weight. I don't know about the Flashpaq instructions, but the AEV ProCal says to take a tape measure and get the actual height. That being said, I've had the best shifting points from getting closer to 32" setting, I backed it down to 31.5"
This evening I contacted a friend of mine with a stock 2013 2dr JK. Since his 255x75R17 tires are almost new; I asked him to come over so I could measure them. Using a level and measuring tape I verified how tall his tires are with 35 PSI in them; his tires measure 31.25".
Tomorrow I will verify the MPH with a GPS and then I will correct the tire size in the TUPS programming.