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Old 11-07-2019, 03:45 PM   #34
Dadhawk
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Quote:
Originally Posted by davesrave View Post
Good article, Thanks. It would have been interesting, though, if they used their "highly precise Datron optical fifth-wheel equipment" to compare odometer readouts vs actual. I guess I can read between the lines and say if there were an issue, they would have mentioned it.
Yea that would have been interesting. Odometers are relatively accurate but not 100%. Used to be that they rolled backwards in reverse which is why you could take a hand drill or other tool and literally turn back time (well miles) on a car (pre-70ish I think is when that stopped).

Current ones are more accurate but could be impacted by a change in tire size, just like a speedometer. They are also impacted by tire wear. As the tire wears, it becomes smaller making the odometer reading higher.

If the odometer is based on a 24.6" tire (that is new calculated circumference of a P215/45R17 tire) for every 1/8" of tire tread wear you gain 25 feet of measured ground per odometer mile. That means for every 211 miles you travel your odometer would be +1 mile off.

Now, I'm not sure if odometers are calculated for medium tire wear so that it balances out over time or not, of if some odometers use a different measurementh other than tire rotation and size.
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