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Old Thu, March 4th, 2010, 12:10 PM
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Gryphon CTS
 
Join Date: Nov 2009
Location: Harrisburg, NC
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Quote:
Originally Posted by gilsnuxs View Post
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.
Unloaded circumference is 2662mm. Allowing a 3% squish factor = 2662 x .97 = 2582mm

Double check:

10.3/10.7 = .96

2582/2680 = .96

Also make sure that you are properly saving the custom settings.

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