How to Change Axle Gear Ratios: Speedometer Calibration & Pricing

Upgrading your rear axle gear ratio (ring and pinion set) is a common way to improve acceleration or compensate for larger tires. However, this modification requires precise installation and speedometer recalibration.

Speedometer Recalibration

Because speedometers measure transmission output shaft speed rather than actual wheel speed, changing the rear axle ratio will cause the speedometer to read incorrectly. Recalibration requires installing a new speedometer drive gear or updating the vehicle's engine control module (ECM).

Installation Costs

Replacing a ring and pinion set is a precise job that requires setting gear backlash and pinion depth. Professional installation is highly recommended to prevent gear whine and premature wear.

Verify your speed calibrations using the automotive gear ratio calculator. For performance benefits, refer to our guide on the performance benefits of short gearing.