Why does the steering wheel shake at 120 km/h after changing new tires?

[VioletMarie]

This situation is most commonly caused by issues with the car tires. When the mass distribution of various parts of the tire is uneven, it can lead to dynamic imbalance when the wheels rotate at high speeds, resulting in severe steering wheel vibration during driving. In this case, it's necessary to perform a four-wheel alignment and dynamic balancing on the car tires. Here are the solutions: 1. Check if the tread is cracked. Aged tire rubber hardens and cracks, indicating the tire has reached its replacement limit, with reduced grip and increased risk of rupture due to external impacts while driving. 2. Check if the tread is cut or punctured by nails. These can cause air leaks and eventual tire blowouts, posing safety hazards if not detected in time. 3. After a tire impact, promptly check for bulges on the tread. A bulge indicates broken sidewall cords, signaling potential imminent tire failure. 4. Visit a tire repair shop to use a tire balancing machine to identify imbalance points and determine appropriate counterweights. It's best to balance all four tires together, or at least the two front tires.