Vehicle speed (mph), engine speed (rpm), tire diameter (inches), trans gear ratio, and rear axle gear ratio are all interrelated. If you know four out of five of these values, you can determine what ...

For part two of our series about transforming Jared Lehenbauer’s new-to-him ’01 Ford F-250 into a truck that’s better suited to his needs, we’re detailing how to select the correct gear ratio for two- ...

Dear Car Talk: Can you tell me why tire sizes are designated as they are? If I understand correctly, we have metric, English and a ratio. Like, a “235-75R15” tire is 235 millimeters wide, has a ...

Optional axle ratios can tailor pickup truck power and efficiency to suit your needs as long as the gearing keeps the engine in its torque sweet spot. Often overlooked, optional gear ratios play a key ...

The right gearing can make or break a truck. It can provide consistent power going through the gears, good hill climbing ability and good fuel economy. As a bonus, it will also help the clutch last.