Speedometer Drive Gear Calculator

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


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.

If you need to calculate your Tire Diameter, click on the  icon
to open the Tire Diameter Calculator.