Speedometer Correction Calculator

How Far Off is Your Speedometer?

To calculate your speedometer difference enter the information for the old tire size, new tire size, old gear ratio, new gear ratio and speed reading. If you are not changing gears, enter the same value for both old and new gear ratio (you can just enter a 1 in both fields, the number is not important if they are both the same).
Old Tire Diameter:
New Tire Diameter:
Old Gear Ratio:
New Gear Ratio:
Speedometer Reading:
Calculated Speed:
Speedometer Difference:

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