Pulley systems are simple machines that make lifting heavy objects easier. They consist of a rope or cable that passes over one or more wheels (pulleys). A single pulley changes the direction of force ...

A gear close gearA gear is a mechanical part with teeth that interlock with another gear or belt to transfer motion and power while changing speed, or direction in a mechanical system. is a special ...

Pro road racers who use Berner's uniquely oversized rear derailleur cages have sworn time and again that they reduce drivetrain friction thanks to their humongous 15-tooth pulleys. Now, Jason Smith of ...