Thread: What is my speed? Got 3 readings!
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Old Thu, February 4th, 2010, 11:12 AM
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Jackpine Jackpine is offline
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Quote:
Originally Posted by longshot270 View Post
An to add to what 88 said, the easiest way to get your tire size correct is just driving for a while after clearing the odometers and using this simple formula.

Truck odometer/GPS odometer x current TS= New TS

Since you are using the odometer you dont have to try matching a number on the GPS with a number on the programmer or truck. To make the calculation more precise drive at least 10 miles. The further you drive the more exact the percentage will be when you multiply by the tire size.
You can even apply Longshot's excellent approach without a GPS. The mileage markers on an interstate are quite accurate. If you drive a measured distance using the mileage markers, you can divide your truck's odometer reading by that, instead of a GPS value.

The farther you drive using either approach, the more accurate your correction will be.

- Jack
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