Friction Wheels:
Friction wheels are a set of two wheels located one next to the other. Motion is transmitted between the wheels (driver and driven) by the friction between them.
Transmission Ratio:
It’s the ratio between the size of the friction wheels and the speed of rotation:
Belt and pulley system:
The system is madeup of two pulley wheels joined by a belt that slots into the grooved rim of the wheels.
Gears
It is a mechanism consisting of two wheels with teeth.
Chain and sprocket systems
These systems consist of two toothed wheels separated by a distance and connected by a chain that meshes with the teeth of the two wheels.
Worm gear:
This rotary transmission mechanism consists of a worm that is fitted to the driver shaft and a toothed wheel that is fitted to the driven shaft.
Elías and Christian 