Bicycle sprocket structure with four-section elliptical arcs and design method thereof having better efficiency, and capable of customizing the bicycle for different users

Disclosed are a bicycle sprocket structure with four-section elliptical arcs and its design method. The disclosed includes a step of testing the pedaling force with the right and left feet, a step of generating important parameters, a step of generating the outline shape and a step of completing the final tooth shape. The bicycle sprocket structure has a sprocket rotation center, a first X-axis radius, a first Y-axis radius, a second X-axis radius and a second Y-axis radius. The first Y-axis radius is equal to the first X-axis radius; values of the first X-axis radius divided by the second X-axis radius and the second Y-axis radius divided by the first Y-axis radius are both equal to the ratio of the right and left foot pedaling forces, that is defined as the value of a user's right foot pedaling force divided by the left foot pedaling force. Furthermore, a sprocket outer edge is located outside the sprocket structure, which consists of an upper point, a right point, a lower point, a left point, a first ellip