It may be because the balance ability of the wheels decreases after high-speed driving, so dynamic balance can be done. The wheel of a car is a whole composed of tires and wheels. However, due to manufacturing reasons, the mass distribution of all parts of the whole can not be very uniform. When the automobile wheels rotate at high speed, it will form a dynamic unbalanced state, which will lead to wheel jitter and steering wheel vibration when the automobile is driving.