Why does the car shake at 40-60 km/h?
3 Answers
If the steering wheel shakes, there could be many factors, but the most common issue is related to the car's brake discs. It is recommended to contact the maintenance department at the sales point to replace both the brake pads and brake discs in a timely manner. Remember, both must be replaced together; replacing only one will not solve the problem. More details are as follows: 1. Common causes: Slight shaking in a car is normal, but if the shaking is severe, it is necessary to check the engine and chassis conditions. The most common cause of car shaking is a dirty throttle body or excessive carbon deposits on the fuel injectors. 2. Excessive carbon deposits causing shaking: When there is too much carbon buildup inside the engine, the gasoline sprayed by the cold start injector will be largely absorbed by the carbon deposits, resulting in a lean mixture during cold starts and making it difficult to start. In this situation, the car will only start easily once the carbon deposits have absorbed enough gasoline to become saturated. After starting, the gasoline adsorbed on the carbon deposits will be sucked into the cylinder by the engine's vacuum suction force and burned, making the mixture too rich. This alternation between lean and rich combustible mixtures causes the engine to idle roughly after a cold start.
Experiencing shaking within a specific speed range, such as 40 to 60 kilometers per hour, is something I've encountered several times. The most common culprit is often the dynamic balance issue of the tires—either the balancing weights have fallen off or were incorrectly installed, leading to imbalance at critical speeds that causes shaking. Another possibility is slight deformation of the wheel hub, similar to when driving over potholes unnoticed over time, causing the hub to warp and transmit vibrations to the steering wheel, resulting in wobbling. Additionally, wear or looseness in the drive shaft or axle, such as aging components resonating more at high speeds, can exacerbate the shaking. Even issues with the braking system can contribute, like unbalanced brake discs causing the car to tremble during braking or acceleration. In short, don't delay—take it to a reliable repair shop for a comprehensive check of the tires and drivetrain. Ignoring it could not only harm the car but also pose safety risks.
My car used to shake violently at around 50 mph, which made me quite nervous. Later, a mechanic friend told me that it was mostly due to uncalibrated tire dynamic balance or shifted balancing weights. It could also be loose wheel bearings or suspension components, like aging rubber bushings causing wobbling, or a bent front axle leading to overall instability. Additionally, engine misfires within a certain RPM range can indirectly cause shaking, such as worn spark plugs or abnormal ignition coils. I tried checking it myself by first ensuring even tire pressure, then starting the car in neutral to listen for any unusual noises. If left unresolved, this shaking will only get worse, so it's best to address it quickly to avoid higher repair costs.
