MPH Formula

This formula allows you to calculate how fast your 4x4 will go with those new tires and gears. Just plug in the RPM you want to run at, the true tire diameter (as measured on the vehicle, not the number marked on the sidewall) with your trans and axle gear ratios. The MPH will be calculated for you.

RPM

True Tire Diameter

Transmission Final Gear Ratio

Axle Gear Ratio

MPH =