What causes the 40-shake to exceed the non-shake?

[DanielaMarie]

40-shake exceeding non-shake is caused by carbon deposits in the engine throttle intake pipe combustion chamber, ignition system malfunctions, and other reasons. Specific causes: Carbon deposits in the engine throttle intake pipe combustion chamber, forgetting to release the handbrake, insufficient engine oil, poor oil supply, low-quality engine oil, excessive spark plug gap, insufficient tire pressure causing imbalance, and aging engine components leading to shaking. Solutions: Severe engine carbon deposits—clean the fuel system; check if the idle motor has carbon deposits and clean it thoroughly; ignition system malfunction—check if the spark plugs have excessive carbon deposits and replace them if necessary; unstable oil pressure—inspect the oil pressure and replace components if needed; check engine components and replace any damaged parts.

[SavannahRose]

That day when I was driving my car, as soon as the speed went over 40 km/h, the steering wheel started shaking like a sieve, which really freaked me out, so I quickly pulled over. Later, I drove to a repair shop recommended by a friend, and the mechanic checked it and said it was a tire balance issue—the four wheels were spinning unevenly, wobbling like a washing machine during the spin cycle. He also mentioned checking the suspension system, as loose springs or shock absorbers could cause the car to sway. If it got worse, it might be due to worn wheel bearings or a bent drive shaft, especially common in older cars. If left unrepaired for too long, not only would driving be uncomfortable, but even braking could be affected, increasing the risk of accidents. So I immediately got a four-wheel alignment and replaced the tires. Now it drives much steadier, and I make sure to clean the mud off the wheels during car washes to avoid imbalance.

[DanteMarie]

I remember once on a long drive, whenever the speed exceeded 40 mph, the car body shook violently, even the seats were vibrating. Experience told me it was most likely due to improper tire balancing, or possibly deformed rims or uneven tire wear from aging. Suspension system issues could also be the culprit, like leaking shock absorbers or loose ball joints, all needing careful inspection. If not addressed promptly, high-speed driving becomes risky and fuel consumption spikes. Some roadside shops use crude methods for balancing with poor results—I recommend professional shops with dedicated equipment for testing. Since then, I check tire tread depth quarterly to ensure even wear on both sides, and make it a habit to walk around the car checking tire pressure before driving—prevention is key.

[SerenityDella]

As a car enthusiast who loves tinkering with vehicles, if my car starts shaking after reaching 40 mph, it's mostly due to tire imbalance or suspension issues. First, I check the tire pressure myself to ensure it's consistent across all wheels—if not, I inflate them immediately. Then, I shake each wheel by hand; if there's any wobble, it might indicate a bad bearing. For the suspension, I look for signs of oil leakage, especially around the shock absorbers. When the dynamic balance is off, the wheels don't rotate smoothly. A simple test is to drive on a flat road and listen for unusual noises or notice changes in vibration patterns. If I can't fix it myself, I either buy a portable wheel balancer to try or head straight to a professional shop for adjustment. Remember, don't overlook brake pad wear—sometimes a dragging brake system can also cause shaking.