What are the reasons for body vibration when the vehicle speed exceeds 120 km/h?
3 Answers
The reasons for body vibration when the vehicle speed exceeds 120 km/h are as follows: misalignment of the front wheel alignment angles, excessive toe-in; low front tire pressure or tire imbalance due to repairs or other reasons; deformation of the front wheel rims or uneven number of tire bolts. When the car wheels rotate at high speed, dynamic imbalance occurs, causing wheel vibration and steering wheel shaking during driving. Here are specific countermeasures: Lift the drive axle, place safety blocks in front of the wheels, start the engine, and gradually shift to higher gears to make the drive wheels reach the final test vibration speed. If both the body and steering wheel vibrate, it is caused by the drivetrain; if the final vibration speed is reached without vibration, the cause lies in the front axle. Check whether the front wheel alignment angles and toe-in meet the requirements, and adjust if misaligned. Lift the front axle and test the wheel rotation, checking the static balance of the wheels and whether the tires are excessively deformed. If necessary, replace with a good wheel for comparison. Check whether the front axle and frame are deformed, and whether the drive shaft is bent. If possible, perform dynamic balance testing on the drive shaft. Check the stiffness of the front leaf springs, the effectiveness of the shock absorbers, and whether the spring bracket rivets are loose. Replace if performance is inadequate. Check whether the chassis is loose and whether the ball joints are worn out.
I've had a similar experience where the car body starts to shake when the speed exceeds 120 km/h. The most common cause is poor tire dynamic balance. If the weight distribution of the wheels is uneven during manufacturing or use, high-speed rotation will generate vibrations that transmit to the car body. Uneven tire wear or slight bulges can also worsen the situation. Additionally, damaged or deformed wheel hubs can also cause shaking. When maintaining my own car, I found that not checking the dynamic balance for a long time can easily lead to problems. Uneven tire pressure is also a potential factor. To avoid safety hazards, it is recommended to perform a tire balance test every 10,000 kilometers. Pay attention to the condition of the tires while driving, and address any abnormalities promptly to prevent high-speed shaking and even extend tire life.
As an experienced driver, I've encountered high-speed body vibration issues, often related to suspension system failures. For example, wear on the front suspension's control arm ball joints or aging shock absorbers can lead to insufficient suspension support, causing the body to sway unstably. Warped brake discs can also induce vibrations at high speeds due to uneven friction. Tire imbalance is another common cause. Neglecting these hidden dangers may lead to a risk of losing vehicle control. My approach is to first try reducing speed to a safe range; if the vibration decreases, promptly visit a repair shop for inspection. Regular maintenance includes replacing aging components, such as evaluating shock absorbers every 50,000 kilometers. Developing good driving habits can also help reduce such problems.