What Causes the Car Body to Sway Left and Right When Passing Over Speed Bumps?

[OCecilia]

The reasons for the car body swaying left and right when passing over speed bumps are as follows: 1. Unbalanced Wheels: During manufacturing, it's impossible to ensure uniform quality for both tires and steel rims, so wheels must undergo dynamic balancing after assembly. As tires wear over time, periodic dynamic balancing is required at certain mileage intervals. 2. Loose Suspension Framework: The chassis suspension consists of various links and support arms connected through ball joints and rubber bushings. Increased wear of these components leads to looseness in the suspension, causing the car body to sway. 3. Excessive Steering Gear Clearance: The vehicle's steering system converts the rotational motion of the steering wheel into wheel oscillation via a rack and pinion mechanism. Over time, wear between the gear and rack creates play, allowing slight left and right wheel oscillation even without steering input, which can make the car body feel unstable.