A wheel is a circular component intended to rotate on an axial bearing. The wheel is one of the main components of the wheel and axle, one of the six simple machines.
In conjunction with axles, wheels allow heavy objects to be moved easily, facilitating movement or transportation while supporting a load or performing labor in machines. Wheels are also used for other purposes, such as a ship’s wheel, steering wheel, potter’s wheel, and flywheel. Typical examples are found in transport applications.
A wheel significantly reduces friction by facilitating motion by rolling together with the use of axles. For wheels to rotate, a moment needs to be applied to the wheel about its axis, either by gravity or by applying another external force or torque.