Gearing Calculator

This page allows you to compare various gear ratios and tire sizes to find your engine RPM in each transmission gear. Final Drive, Transmission Ratios, and Tire Diameter can all be manually edited if needed. For automatics, it is assumed the convertor is locked. Convertor slip varies based on load and RPM so it is hard to model accurately. Note on torque calculations: Output Torque is calculated assuming no drivetrain loss. It is not the same as the rear wheel torque from a chassis dyno, as that is calculated based on horsepower and RPM. This number can be used to show differences in torque multiplication with different tire sizes and gear ratios. Remember, gearing is not just about RPM!