Why does the car sway from side to side on rainy days?
3 Answers
On rainy days, the car sways from side to side because water has inertia, which can disrupt the vehicle's balance. Here are the detailed reasons and solutions: 1. Reasons: Water has both higher density and resistance compared to air, so movements in water are slower than on land. Similarly, when a vehicle passes through accumulated water, once the water depth reaches a certain level, you will clearly feel a force pushing against the vehicle. If only one side of the vehicle passes through the water, since both sides have the same inertia while driving, encountering resistance on one side will disrupt the vehicle's inertial balance. Additionally, the sudden change in tire grip leads to the car being pulled and swaying from side to side. 2. Solutions: When driving on rainy days, if you encounter accumulated water ahead, do not rush through it, and try to avoid passing through the water at high speed on one side.
After driving for so many years, I've found that the car swaying left and right on rainy days is usually a tire issue. When the road is slippery, poor tire grip can make the car unstable, especially if the tire pressure is incorrect or the tread is severely worn. If the tread is too shallow, the water drainage effect is poor, and water accumulates under the tires, causing skidding and swaying. I recommend checking the tires regularly to see how many millimeters of tread depth remain—if it's too shallow, replace the tires promptly. Also, maintain the tire pressure at the recommended level, as both overinflation and underinflation can worsen the swaying. Drive slower in the rain, keeping the speed below 80 km/h to reduce risks. Pay attention to tire condition regularly—preventive measures are more cost-effective and hassle-free than repairs after the fact.
As someone who enjoys studying automotive mechanics, I believe the shaking on rainy days is mainly related to the suspension system. When suspension components age, their shock absorption performance deteriorates, making the car more prone to swaying left and right on wet and bumpy roads. If the shock absorbers are worn out or the stabilizer bar is deformed, the shaking becomes more noticeable when washed by rainwater. I recommend developing a habit of checking the suspension condition, such as looking for oil leaks or squeaking sounds from the shocks. Get a comprehensive adjustment before the rainy season to ensure a steadier ride. Also, pay attention to unbalanced vehicle loads, which can affect shaking—avoid overloading the trunk. Simple suspension maintenance can save you a lot of unnecessary trouble.
