The Hypertech Speedometer Calibrator can correct your speedometer for non-stock tires and/or gear ratios. The simple on-screen menu quickly guides you through the process, and in a matter of minutes the vehicle's computer is reprogrammed for accurate readings.

Speedometer Calibrator

If you’ve installed tires that are larger or smaller than original equipment tires, or if you have installed a ring and pinion gear set with a different rear gear ratio, the Speedometer Calibrator allows you to re-program for correct speedometer readings, as well as correct part-throttle shifting. The vehicle’s computer calculates your vehicle’s speed based on the diameter of the stock tires. If you’ve installed taller or shorter tires, or changed the rear gear ratio, the vehicle’s computer doesn’t know how fast your vehicle is going. As a result, the automatic transmission may not shift correctly and the speedometer readings will not be accurate (as required by law).