Gryphon won't correct tire size

[Longshot270]

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.

Ok, dont worry about squish when you use this formula. The tires size in the programmer should already compensate for that.
I'm not at my computer right now but I think when I put in my tire size and play with the amount of squish it comes out to 4.5 or something like that for 235/70-17 tires on an 8.5 inch rim. Try using the 2763. This method isn't always a one shot deal sometimes. Things like GPS errors and incorrect tire size values can throw it off.

Haha and I didn't see you other guys post.