post your true tire diameters
03-13-2014, 04:34 PM
#23
JK Freak
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I have 255 Rubicon BFG MT. I measure the rolling circumference and divided by PI. This gave me the diameter of 30.75. I programmed my Procal with that number, and the speedometer is right on the money. I checked it with 2 different GPS's.
03-13-2014, 05:18 PM
#25
JK Enthusiast
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Measuring to the bottom while parked may be different when park than when in motion though correct? Wouldn't centrifugal force cause the center of the tire to expand thus creating a different radius/diameter? May be thinking of this wrong and or maybe change is so minor that it doesn't matter
03-13-2014, 05:21 PM
#26
JK Enthusiast
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This would likely be the most accurate way to calibrate a speedometer but ... for the reasons mentioned by Planman, not an accurate way to measure resting tire height.
