The Ring Gear & Pinion is the automotive hardware that rotates the wheels of a car backwards and forwards. They are commonly used in the the drive systems of tractor-trailers and larger pickup trucks meant to carry heavy loads. The pattern refers to how the ring gear and pinion gears mesh. There is a process used when reassembling a differential that optimizes ring gear and pinion tooth contact. The offered Ring Gear & Pinion is made for use in the various industries.