What Causes Car Vibration at High Speeds?
4 Answers
Reasons for car vibration at high speeds: 1. Ignition system failure: Issues with spark plugs, high-voltage wires, or ignition coils can lead to poor ignition system performance, triggering the engine warning light accompanied by vibration. 2. Overly rich air-fuel mixture in the cylinders: This may cause knocking and vibration. 3. Abnormal fuel supply pressure: This can also result in car vibration. 4. Faulty idle control valve or wiring. If the engine warning light flashes and the car shakes, it is recommended to stop immediately for safety, avoid continuing to drive, and call a 4S shop or professional auto repair shop for assistance, requesting a tow truck or waiting for rescue.
Yesterday while driving on the highway, my car suddenly started shaking violently, and even the steering wheel was wobbling, which scared me into slowing down immediately. This kind of high-speed shaking is usually caused by tire issues, such as improper wheel balancing, deformed rims, or bulging/tire deformation, leading to uneven rotation. I once had a tire repaired without wheel balancing, and it shook terribly above 80 km/h—it was only resolved after reattaching balancing weights. If the rim gets deformed after an impact, it can cause the same problem. Tire bulges are even more dangerous, as they can easily lead to blowouts at high speeds. Besides tires, worn suspension link bushings or bent drive shafts can also cause vehicle vibration. It's recommended to first check the wheel balancing and then inspect the chassis components—safety comes first.
The most common cause of body shaking at high speeds is warped brake rotors. It shakes even more when you apply the brakes, right? That's because uneven heating causes the rotor surface to become uneven, and the brake pads gripping it transmit vibrations to the steering wheel. I experienced this right after replacing my brake rotors, especially noticeable after frequent braking on mountain roads. Of course, tire issues can't be ruled out either—things like out-of-round wheels or lost wheel weights can also cause vibrations. Additionally, loose steering ball joints can amplify the shaking sensation at high speeds. It's best to have a shop check the rotor flatness with a dial indicator. If needed, have them resurface the rotors and perform wheel balancing while you're at it.
For rear-wheel-drive cars experiencing high-speed vibrations, focus on the driveshaft. Worn universal joints or imbalanced driveshaft rotation can cause the entire body to tremble. In front-wheel-drive vehicles, bent half-shafts often induce resonance, particularly noticeable around 90 km/h. Last time I repaired an Audi A4 with high-speed vibrations, it was caused by a damaged inner CV joint making the half-shaft operate unevenly. Additionally, excessive wheel bearing wear with large clearance can transmit vibrations. Such issues require prompt repair to prevent worsening damage - in severe cases, half-shafts may fracture. Check driveshaft runout; if exceeding 5mm, servicing is necessary.
