4 reasons why cars vibrate and shake when operating

1. Tires

After a period of use, the tire wears unevenly, and there will be “heavy spots” and “light spots” on the tire surface. If the “heavy spot” is in the middle of the tire, it will cause the vehicle to bounce when driving; in the case that the “heavy spot” is on the side of the tire, it is called “dynamic” imbalance. This causes the tire to sway back and forth when driving.

Tire imbalance starts to be felt at around 50 km/h and is most noticeable at around 80 km/h. If the vibration is felt coming from the steering wheel, the front tires should be checked, if the vibration is felt more in the seats, the rear tires should be balanced.

2. Wheel rims

When driving, the rim hitting the curb may not cause damage, but if you pay attention, the car may vibrate afterwards. This is because the rim or half-shaft is bent, causing the rotation of the wheel to be out of orbit, causing vibration, or simply losing the support bars used in dynamic balancing.

A bent rim or axle should be checked with a gauge to measure the offset. Most manufacturers allow no more than 1/32 of an inch of offset. Steel rims can be straightened. Aluminum rims (cast) must be replaced.

3. Transmission system

The transmission system includes parts such as: gearbox, cardan shaft, joints, main transmission, differential... used to transmit motion from the engine to the wheels. During the working process, these parts participate in continuous rotational movements, so damage or wear of the parts in this cluster can also cause vibration and shaking of the vehicle.

In addition, worn or loose universal joints can cause vibration, especially during acceleration and deceleration. This is understandable because the rotation speed of the universal shaft is 3-4 times greater than the rotation speed of the wheel. It is necessary to check the universal joints, if loose, they should be replaced. Continuing to use a worn universal joint can cause it to break, not only causing the vehicle to vibrate but also causing unpleasant noise.

4. Brake system

Vibration when braking indicates that the brake drum or disc may be warped, warped or unevenly worn on the surface. In addition, if the surface of the brake drum or disc is too dirty, it can also be the cause of this phenomenon. This is most obvious when the vehicle is moving at high speed, because at that time these rotating parts are subjected to uneven impact force from the brake pads, causing large impact force, causing vibration and jerking.

To fix the problem, the technician must remove the brake disc or drum, clean it, and straighten it if it is warped.