Why Does the Steering Wheel Shake When the Car Exceeds 120 km/h?
3 Answers
The main reasons for steering wheel shaking when the speed exceeds 120 km/h are as follows: 1. Feedback force generated by the contact between the tires and the ground. 2. Inward or outward tilting of the car wheels. 3. Presence of foreign objects on the tire surface. 4. Loss of wheel balance weights. 5. Deformation of the wheel hub. 6. Excessive clearance in the steering linkage. 7. Insufficient tire pressure. Specific issues related to car tires can be divided into the following points: (1) Uneven tire pressure among the four wheels. (2) Uneven tread wear among the four wheels. (3) The wheel rims of the four wheels are not perfectly round. (4) No alignment correction was performed after replacing the tires on the four wheels. (5) A foreign object punctures one of the tires and forms a bulge on the tread, which is not noticeable at low speeds but becomes very obvious at high speeds due to the frequency vibration generated.
I've been driving trucks for twenty years, and steering wheel vibration is all too common. If it shakes when going over 120 km/h on the highway, nine times out of ten it's due to improper tire balancing. When the weight distribution of the four wheels is uneven, high-speed rotation causes chaotic shaking, just like a washing machine spinning clothes. Another possibility is wheel rim deformation—last time I hit a pothole without slowing down and bent the rim, making the steering wheel shake so badly my hands went numb. Worn suspension system components can also cause this, especially when the control arm bushings age. You need to get to a repair shop ASAP—start with a wheel balancing check, and if that doesn't fix it, inspect the suspension. Remember, never ignore steering system issues; sudden loss of control at high speeds is no joke.
Last week I picked up my new car and noticed severe steering wheel vibration above 120 km/h on the highway. The sales manager told me this is usually a wheel issue, especially if the tires were replaced without dynamic balancing. I specifically went to a tire shop for inspection—the technician kept attaching lead weights to the rim as it was slightly out-of-round. They also taught me to check tire wear: sawtooth tread patterns can cause shaking. Additionally, a deformed driveshaft transmits vibrations; my colleague’s off-roader vibrated after hitting a rock that bent its driveshaft. Now my car runs rock-solid even at 150 km/h—money well spent.
