Speedometer Drive Gear Calculator

Quickly calculate your speedometer drive gear size for your transmission with this easy to use calculator


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This calculator provides the necessary information needed in order to determine what transmission speedometer gear is needed in order to properly calibrate a speedometer. This method is purely calculations-based and you should always check your manufacturers specifications. Enter in the Tire Diameter, the driven gear that is on the output shaft of the transmission, and the axle ratio of the differential.  Once you have entered those fields in click Submit.

This calculator will give the number of speedometer gear teeth, by rounding the nearest "tenth" of a tooth up or down the the closest whole number. This tool is only a reference, and you should always refer to the manufacturers specifications before installation

Speedometer Drive Gear Calculator
Tire Diameter (in):
Driven Gear (7 - 44):
Axle Ratio (< 10):
Tire Diameter Calculator

Tire Width

Aspect Ratio

Rim Diameter

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