A chain wheel used in a drive is a way of transmitting mechanical power from one place to another. Most often, the power is conveyed by a roller chain, known as the drive chain or transmission chain, passing over a sprocket gear, with the teeth of the gear meshing with the holes in the links of the chain. The chain wheel is rotated, and this pulls the chain putting mechanical force into the system.

Chain wheels can be simplex, duplex, triplex or quadplex.