What Causes Body Shaking at 120 km/h?
4 Answers
When driving at 120 km/h, the phenomenon of body shaking occurs due to poor dynamic balance of the two front wheels. If there is a pressure difference between the tires, the wheels' ability to absorb vibrations varies, which can also cause the vehicle to shake. Additionally, deformation or bending of the drive shaft and excessive wear of the drive ball joints can lead to vehicle shaking. Meaning of Dynamic Balance: For wheel alignment, it is mainly applied when the vehicle tires exhibit deviation. In terms of the tires themselves, there is no inherent issue. Wheel Alignment Adjustment: It includes four operational details: kingpin inclination angle, front wheel camber angle, front wheel toe-in, and kingpin rear angle. Simply put, wheel alignment is based on the situation where the tires experience edge wear during driving. The tires themselves do not have significant wear, so performing a wheel alignment ensures stable straight-line driving and easy steering. It can reduce wear on steering components and front wheels during driving.
I've been driving for decades and have encountered many instances of shaking at 120 km/h. The most common cause is wheel imbalance—when the tires rotate unevenly at high speeds, even the steering wheel can shake. Sometimes, deformed rims or bulging tires can cause the same issue. If you don’t perform a wheel balance after replacing tires, you’ll feel it immediately. A bent driveshaft can also induce resonant vibrations, especially in rear-wheel-drive cars. Warped brake rotors are another hidden culprit; they cause intense shaking when braking, but even slight vibrations may occur at high speeds without braking. These issues must be addressed promptly, or they’ll worsen and damage the car over time. Aging suspension components, like loose ball joints or cracked control arm bushings, can also lead to wheel misalignment and shaking.
I guess you're experiencing shaking issues at 120 km/h? The main focus should be on checking the tires. The most common cause is lost wheel balance weights - getting a wheel balance at a tire shop costs just a few dozen yuan. Also check tire pressure, as significant differences between the four tires can cause shaking. Wheel rim deformation is more troublesome and may require replacement. If the driveshaft CV joint is damaged, you'll feel jerky vibrations when accelerating. Another small detail: when engine mounts deteriorate, engine vibrations transfer to the car body, especially noticeable at high speeds. If you've modified the rims, incorrect center bore alignment could also cause shaking. I recommend starting with a simple wheel balance check before considering major repairs.
Vibration at 120 km/h is mostly wheel-related. Improper wheel balance causes body resonance, making the entire car feel shaky. Tire bulges or uneven wear are also common causes – carefully inspect the tread. A deformed driveshaft, especially the half-shaft on front-wheel-drive vehicles, causes noticeable vibration at specific speed ranges. Worn wheel bearings produce humming sounds along with vibration due to rotational imbalance. While warped brake rotors aren't noticeable at low speeds, heavy vibration occurs when braking at 120 km/h. Incorrect wheel alignment can also cause instability, though it primarily leads to pulling. None of these checks are complicated – a reputable repair shop can quickly diagnose the issue.
