Just upgraded the stock 32" wheels (2018 Platinum) to 34" wheels. Speedo reads about 5mph lower at 70mph. Has anyone had any luck using ForScan to adjust the speedometer readout? I tried changing the tire circumference from the stock 2478mm to 2735mm, but the car keeps throwing DTC codes and stating that the tire circumference is out of range. In fact, even a single mm above the stock 2478mm will cause this. BCM and TCM relearn and DTC clear doesn't help. Keep getting the same "out of range" error.
From what I read on ForScan forums, the min-max range is hardcoded.
Is there another way to recalibrate the speedometer? i.e. changing values for differential, etc.