GEAR The pulleys and gearing have the problem of displacement, especially when efforts are to transmit are high. In these cases they are used to enable transmission gears with high precision efforts. The gears are pairs of gears that are strung between them, so that turning the other one rotates counterclockwise.They are used to multiply or reduce the forces to change direction and to increase or decrease the rotational speed of the shaft on which are placed. So if we have two different sized gears that are embedded in the same plane, but will the small wheel turns the big wheel at the same time. Thus, if the big wheel drag the small, get a speed increase and, conversely, if the small wheel that drags large, get a speed smaller. There are four basic types of gears.