Accuracy of speedometer

[Cycliste]

You'll love this one then. very economical. Also the only way to get real cruise control without a trailer attached

Switch to metric, and your number would have been 179

Want to drive over 100? One weird trick cops hate…

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[Dave Cundiff]

FWIW, calibrating to interstate mile markers in the stretches where all markers appear plausible, and using factory tires except on the Rivian:

Our 2017 and 2018 Kia Optima odometers both read 2.2% below actual miles traveled.
Our 2019 Bolt odometer reads 0.5% above actual miles traveled.
Our 2023 Bolt odometer reads 0.5% below actual miles traveled.

Our 2023 R1S, after replacing 21" factory tires with 275/50R22 winter tires - within 0.3% on diameter) reads 0.4% above the actual miles traveled.

So far, the R1S appears to be the most accurate of our recent vehicles.

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In my area, the "Your Speed Is" radar is mostly very accurate (within 1%, when I'm driving straight toward the sign) but sometimes reads 2-4% below my actual speed.

So I still use my odometer to calibrate my speedometer. I presume that modern equipment is even better at calculating the relationship between RPM and total revolutions than the equipment I grew up with.

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Depending on how you're measuring it, a 5% discrepancy between displayed speed and actual speed seems very high to me.

If you're still using factory tires or equivalent, @Manu, it looks as if Rivian owns this discrepancy. I'd contact Rivian Service and expect them to make it right.

Very best wishes!