Simple gear train with two gears (gear ratio in terms of angular velocities and number of teeth)

Description

The gear ratio of a gear train, also known as its speed ratio, is the ratio of the angular velocity of the input gear to the angular velocity of the output gear. The gear ratio can be calculated directly from the numbers of teeth on the gears in the gear train. The simplest example of a gear train has two gears. The “input gear” (a.k.a. the drive gear) transmits power to the “output gear” (a.k.a. the driven gear).

Related formulas

Variables

NBThe number of teeth on the output gear (dimensionless)
NAThe number of teeth on the input gear (dimensionless)
ωAThe angular velocity of the input gear (radians/s)
ωBThe angular velocity of the output gear (radians/s)