The drive sprocket transmits engine power to the belt or chain, which then drives the rear wheel. Its size and number of teeth affect acceleration and top speed: a smaller sprocket improves acceleration, while a larger one increases top speed. On automatic scooters, the sprocket works with a pulley system to continuously adjust the gear ratio, achieving a smoother ride. Proper maintenance of the sprocket and belt is crucial to ensure efficiency, good performance, and fuel economy.