If you've ever driven a car with a broken shock absorber you can experience the bounce that the rear shock absorber is designed to suppress as it bounces through every pothole rippling in its wake. The size of the damping force of the shock absorber increases and decreases with the increase and decrease of the relative speed of the frame and the axle (or the wheel) and is related to the viscosity of the oil. The viscosity of oil used in shock absorber is required to be affected as little as possible by temperature changes; It has the properties of resistance to vaporization oxidation and corrosion of various metal and nonmetal parts.