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 ...

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 ...

You've added the lift and big tires, but you're being outrun on the freeway by aged Yugos, and your 4WD sucks gas faster than an earthmover. Part of your woes may simply be due to the gearing in your ...