Gear Ratio Calculator
Calculate road speed, engine RPM, crawl ratio and differential changes for pickups, transport trucks, tractors and off-road vehicles.
Vehicle Information
Results
Recommendation
Enter your drivetrain information and click Calculate.
Understanding Gear Ratios
Gear ratios determine the relationship between engine speed and vehicle speed. Lower numerical axle ratios generally improve fuel economy at highway speeds, while higher ratios provide greater pulling power for towing, off-road driving and agricultural work.
This calculator is useful for transport trucks, pickups, farm tractors, construction equipment and custom vehicle builds.
Frequently Asked Questions
What is an axle ratio?
The axle ratio is the number of driveshaft revolutions required to rotate the wheels one complete revolution.
What does overdrive do?
Overdrive gears reduce engine RPM at highway speeds, improving fuel economy and reducing engine wear.
Why change tire size?
Changing tire diameter affects engine RPM, road speed, fuel economy and speedometer accuracy.