The term gear ratio is used to express the comparison of the speed of rotation between two gears. It is always stated with the first number representing the rotation of the driving gear and the second number representing the driven gear. Also, the first number represents the number of times the driving gear must rotate to make the driven gear rotate one turn.
Some examples of how gear ratio is stated are:
A 1:1 ratio indicates both gears are rotating at the same speed.
A 2:1 ratio indicates that a small driving gear is in mesh with a driven gear twice as big. The driving gear must turn twice to turn the driven gear once.
A 0.6:1 ratio indicates the driving gear is biggest. For every three turns it makes, the driven gear will rotate five times. Therefore, the driving gear only has to make sixtenths of a revolution to rotate the driving gear once.
Gear ratio between gears can be determined by counting the teeth of the driving and driven gear. You must remember that when two gears are in mesh, as the driving gear rotates the distance of one tooth, the driven gear will rotate the same amount. |