The "pop" sound made by a vehicle when passing over a pothole or speed bump is usually caused by a combination of factors. First of all, this sound is most likely the working sound of the vehicle's suspension system. When a vehicle is driving through potholes or speed bumps, the suspension system needs to absorb the impact of the road surface and keep the body stable. When shocks, springs, and connecting rods are used in suspension systems, they move relative to each other and friction to make sounds.
Secondly, the interaction between the wheels and the tires can also be audible**. When a wheel passes through a pothole or speed bump, the tire is subjected to an instantaneous impact and deformation, in which the air inside the tire is squeezed and vibrates, resulting in a sound. In addition, the friction between the tread on the surface of the tire and the road surface also makes a sound.
In addition, other parts on the chassis of the vehicle, such as exhaust pipes, fuel tanks, etc., may also produce vibration and friction when subjected to road impacts, resulting in sound. These sounds are mixed with the sounds produced by the suspension system and tires to create what we hear as a "poof" sound.
Overall, the "pop-pop" sound that a vehicle makes when passing over potholes or speed bumps is the result of a combination of factors. These sounds reflect, to some extent, the state of operation of the vehicle's suspension system, tires, and other parts of the chassis. If the sound is abnormally loud or accompanied by other abnormal phenomena (such as abnormal vehicle vibration, abnormal chassis noise, etc.), it is recommended to check and repair the vehicle in time to ensure driving safety.