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Discussion Starter #1
Can anyone tell me why my speedometer is three miles over actual speed?
Everything is stock. I find this discrepancy using two different GPS devices and roadside radars. It's quite regular in nature regardless of speed. It seems I am always traveling three miles an hour less than the odometer is telling me.
 

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My B5 reads about 2 MPH higher than actual while my R32 is spot on. Actually the R32 is the first car I've ever owned where it was spot on, 2-3 higher than actual is what all my other cars have been.
 

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Very common in most cars. Keep in mind that wheel and tire size affects the speedometer reading. Since most cars are available with a variety of optional wheel and tire size combinations and there is no way an automaker can calibrate the speedometer for each and every application, they often err on the high side since they don't want to deal with a complaint from a customer who got a speeding ticket when his speedometer said he wasn't.
 

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I'm pretty sure the odometers are right on the money...or am I wrong? :crazy:
Not necessarily but the odometer and speedometer are no longer mechanically connected so their error rates can be different. But the tire size issue will still effect odometers just like speedometers.
 
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