The multi-stage flywheel is based on the single-stage flywheel, adding several flywheel plates and combining them with the sprocket on the central shaft to form various transmission ratios, thus changing the speed of the bicycle.

The working principle of its single-stage flywheel: when the pedal is stepped forward, the chain drives the flywheel to rotate forward. At this time, the inner teeth of the flywheel are combined with the kilo. The rotating force of the flywheel is transmitted to the core through the kilo. The core drives the rear axle and rear wheel to rotate, and the bicycle moves forward.