Because the bicycle is driven by the driving force and riding skills of the human body, the frame becomes an important structure to bear the impact load generated by the bicycle during driving and whether it can carry the human body comfortably and safely. The manufacturing accuracy of the frame components will directly affect the safety, stability, and lightness of riding. Generally speaking, the spokes are of equal diameter. In order to reduce the gravity, they are also made into variable-diameter spokes with large ends and small middle, and they are also made into flat streamline spokes to reduce the air resistance.