Starter ring gear

A starter ring gear, sometimes called a starter ring or ring gear, is a medium carbon steel ring with teeth that is fitted on the periphery of a flexplate or flywheel of an internal combustion engine, mostly for automotive or aircraft applications. The teeth of the starter ring are driven by the smaller gear (the pinion) of the starter motor. The primary function of the starter ring is to transfer torque from the starter motor pinion to the flywheel or flexplate to rotate the engine to begin the cycle.