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How is that? Unless you mess with the spring tension on the speedo needle, your error percentage should be the same between speedometer and odometer.


Never messed with the speedo spring tension, that is just the way it is. Not uncommon for the two to be off. The odometer is a purely mechanical gear driven device, the speedometer uses a spinning magnet and spring to display the speed. So if it is not perfectly calibrated, it can read faster or slower than the odometer.