Gryphon won't correct tire size

[Jackpine]

Originally Posted by gilsnuxs

OK, Ive tried the formula using the odometer and my speedo is still off by the same amount. GPS reads 67, CTS Unit reads 70, and Truck speedo reads 73. Stumped. If it helps, I have Nitto 325/60/18 so I used 2660. Truck odometer was 10.7, GPS was 10.3. I got 1.0388 x 2660=2763 2763-3% for squish=2680. THats what I used.

Looks to me like you've INCREASED your TS for "squish", which would make your CTS read "too fast", A 3% squish on your tires reduces the circumference to 2581. That may be too small, looking at your numbers, but the correct TS should be somewhere between 2660 and 2581.

Edit: You're too fast for me Shotgun! And you were absolutely right.

- Jack