There are many reasons why the brake pads produce abnormal noise when braking, one of which is braking. The inherent characteristics of the components of the hoof and brake pump and brake attachment during braking, If the frequency reaches a common point, noise points will appear; in addition, if the original factory. There is no noise in the brake pads, and the brake pads purchased in the market produce noise. It is not appropriate to determine the formulation of the product.