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 ...

"Give me a lever long enough and a fulcrum on which to place it, and I shall move the world." — Archimedes (287- 212 B.C.) On the street, everything is a compromise. Power is now easier to make than ...

Few vehicle modifications have as major an impact as changing gear ratios, and it's because your car's gear ratio directly translates to how it delivers power. Think about it: The gear ratio, or how ...

Building your 4x4 can be one of the most enjoyable and rewarding adventures that you will ever take. While we understand that not everyone is a master fabricator, simply getting to know the basics of ...

What if-and believe me, this is a hypothetical-you were trying to put a wild, rare, 200-hp naturally aspirated Autech SR20DE from the hottest of the nonturbo S15 Silvias into a first-generation Miata, ...

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 ...