Here, we are concerned not so much with vehicle vibrations, but with the bouncing and swaying of the entire vehicle i.e., the transmission of every unevenness of the road surface to the body. These symptoms appear when the vehicle runs over bumps or uneven road surfaces at particular speeds.
1.Main causes
Bumpy or uneven road surface
Tire vibration
Suspension vibration
2.The development of discomfort
(1)The vehicle body sways when driving over bumps or uneven road surface. These oscillations are transmitted to the suspension.
(2)The oscillations in the suspension cause the vehicle body to bounce repeatedly, making it appear to the passengers that the vehicle is swaying.