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 ...

The optimal gear ratio depends on how the engine fits the intended use of the boat. Courtesy Yamaha In every boat test we run, we include certain specs that we feel are valuable to our readers. Some ...

It's a simple formula that most four-wheelers are intimately familiar with: The deeper your crawl ratio, the more control you have out on the trail, particularly on steep, nasty obstacles. The more ...