Checked it out and that setting is correct. The tire height is 25.5 inches. Took the car out again late yesterday afternoon . The speedometer is very accurate to 25mph (gps) and then starts creeping up faster on the speedometer compared to the gps. Reads 35 when doing 30. Seems like about 1.5 mph faster speedometer reading than the gps for every 5mph increase in speed. Speedometer was reading 70 mph and the gps was reading 59mph. The odometer was spot on though. Our highways are exactly a mile apart and the odometer was dead nuts on that regardless of speed. I don't know. Honestly, I'm more concerned about the correct mileage on the car but the speed difference has got me baffled.