Car Shakes At High Speed – Causes and Fixes

Several issues can cause a car to shake at high speed. Vibrations at high speed are often common warning signs that will escalate to bigger [much expensive] problems if not resolved at an earlier stage.

Car shakes when driving over 70 mph often means different from a car that shakes when accelerating at low speed. So, you need to identify when the vibration occurs to track the culprit and fix it on time.

What if your car shakes at high speed? Low speed? On idle? At constant speed? Or does the vehicle vibrate when braking? There are a plethora of causes of vibration at each stage.

What area should you diagnose? This article will discuss the causes of car vibration at high speed on how to fix it.

What causes car shakes at high speed?

car vibrates at high speed when accelerating

The common causes of a car shaking at high speed are unbalanced tires, loose lug nuts, bent inner CV joints, and lousy spark plugs. Other reasons include a worn-out engine mount, a damaged CV axle, and a disconnected vacuum hose.

Unbalanced tires: If you install new tires on your vehicle and notice vibration at high speed, it could result from an unbalanced tire. Imbalanced tires will deprive you of confidence on the wheel.

When cruising down the road at low speed, an imbalanced tire will cause slight vibration. When you speed up, and your baby ride turns into a road beast, the vibration will increase. As the wheel spins faster, the shaking will become more noticeable and cause the steering wheel to vibrate.

If you notice the vibration at a constant speed and it worsens at high speed, bad tires are likely the culprit.

Loose lug nuts: This is a common issue that happens most times after a visit from a mechanic’s shop. If you or a technician forgets to torque the wheel nuts after working on the suspension, it’ll cause a minor or severe wheel wobble. This will look like the vehicle is shaking.

If you do not tighten the lug nuts on time, they can loosen and fall off. This can be a catastrophe as it can lead to a collision. You don’t want this to happen. After tightening a vehicle’s wheels, cross-check the lug nuts before hitting the road. Ensure you use the correct size.

Use a torque wrench to tighten wheel lug nuts to the manufacturer’s specification. If you don’t have a torque wrench, a sizable socket and ratchet, or the vehicle’s wheel spanner will do the job. Do not overlock the lug nuts, so it will be easy to remove next time.

Bent or damaged inner CV joint: Each axle has two CV joints. We have the inner and the outer CV joints. When the inner front CV joints wear off, the front end of the car will vibrate at high speeds. Failed or damaged back inner CV joints will also cause vibration on the vehicle’s rear end. If overlooked, the minor shakes will escalate to violate shaking.

A common cause of CV joint failure is worn boots. The CV joint boots prevent water and dirt from entering inside the axle. If the boots tear, it’ll allow water and contaminants to wash out the grease on the axle.

The grease prevents metal-to-metal contacts and provides a smooth ride. If there’s little to no grease on the CV joints, it will cause it to fail.

Lousy spark plugs: Dirty or fouled spark plugs can cause engine misfire. If your car vibrates when idle, it can be traceable to foul or dirty spark plugs. It can also cause the vehicle to vibrate when driving.

If you haven’t changed the spark plug for a long time, this may be the right time to clean or replace it. Whichever route you choose – cleaning or replacing- do it on all the spark plugs.

If you remove one and it looks okay, don’t stop. There are chances that oil leaks on the spark plug wells or other plugs are damaged or dirty.

Stuck brake caliper: A sticking or stuck brake caliper can cause a vehicle to vibrate. Here, you won’t feel the vibration itself. The vibration will be noticeable on the steering wheel as you throttle the car to 40-50 mph. 

As you feed more gas to the car, the steering wheel will keep vibrating. The wheels will emit burning-like smells. 

If you suspect a sticking brake, inspect all the wheels by sniffing them to see which wheel emits the burning-like smell. You may notice little smoke in the caliper area. Do not touch the wheel with bare hands as it may burn off your hands.

Brushing and lubricating the caliper pins, sandpapering the rotor, and cleaning the brake components may be what you need to fix these issues.

Broken engine mount: The primary function of the engine mount is to connect the engine to the vehicle body. Another part is to serve as a damper. This means that it reduces vehicle vibration so that the driver and passengers won’t feel constant vibration while traveling.

A broken engine mount causes vibration in a car seat at highway speed. It can also cause misalignment on other vehicle parts since the engine weight is not properly resting where it should.

Faulty engine mounts can cause car shakes at low speed but not high. The shaking will become more noticeable as you speed up the vehicle because the engine works harder.

When one engine mount fails, the other mounts compensate by carrying the vehicle load. This will cause them to break in no time. Sometimes, a broken engine mount affects the transmission mount.

Bent Axle: A vehicle axle is a strong metal component. Strong doesn’t mean it cannot be bent. 

If you had a minor accident or hit a large rock, it could bend the axle. When situations like this surface, don’t assume everything is okay. It could cause some unnoticeable issues which will surface with time.

A bent axle will give noticeable vibration when cruising around 40-50 miles per hour. The vibration will increase as the vehicle increases in speed. Failure to attend to this issue and replace it will cause severe problems with related components.

Bent driveshaft: Driveshaft, also known as propeller shafts, connects power from the front wheels to the back wheels. Rear-wheel drive [RWD], all-wheel-drive [AWD], and four-wheel drive [4WD] vehicles feature driveshaft.

These components can bend over time and cause car shakes when accelerating at low speeds. The vibration will increase as you step on the gas pedal and worsen as the car outbursts speed on the road. A worn-out spicer bearing on the driveshaft joints can cause this problem. Often, a worn-out bearing is why technicians replace a complete driveshaft.

Disconnected or torn vacuum hose: A disconnected or torn vacuum hose can cause air leaks, which will send a wrong signal to various car sensors. These sensors will forward this false signal to the car computer, which will try to compensate by adjusting the air/fuel ratio mixture. The result is car backfires, engine misfires, loss of engine power, and other engine problems.

Engine running rich or lean is a situation you don’t want to experience. Therefore, you need to ensure the engine runs with the correct air/fuel mixture.

car vibrates at high speed when accelerating

How do you fix a shaking car at high?

Since there are many causes of car vibration at high speeds, there are several ways to fix it. This section will highlight several ways to stop vibration at highway speed.

Get a wheel balance: This requires taking the tires to a mechanic or alignment shop. The technician will mount the imbalanced wheel/tire on a balancing machine to correct the imbalance issues. 

Tighten loose lug nuts: This requires a common fix that you can do without visiting a mechanic’s shop. To fix this, park your vehicle on a level and firm pavement. Block off two wheels and cross-check the lug nuts with a torque wrench.

Torque the vehicle to the manufacturer’s spec. If you don’t have a torque wrench, use the vehicle wheel spanner. Do not over-tighten it as it could wear or break the lug studs.

Replace defective or failed inner CV joints: As alluded to above, one of the common causes of bad inner CV joints is torn CV joint boots. The only fix is to replace the joint with new boots.

Clean or replace spark plugs: A fouled or dirty spark plug will not provide the required spark needed to keep the engine running as it should. You can fix this issue by cleaning old sparking plugs or replacing them with new ones.

Service calipers: If inspection proves that the caliper is the culprit of the shakes at the highway, you may have to service the caliper by cleaning and smoothing the pistons. Check the caliper pins and ensure they are working as they should. The next thing to consider is to get a new caliper and assembly.

Replacement of broken engine mount: Most engine mounts are not repairable. Though, you can repair some by changing the bushing inside the side.

Once you notice a broken engine mount, drive to a mechanic shop for a replacement. I recommend disassembling all engine mounts and inspecting them on the floor.

For example, two mounts out of three may damage; inspection shows only one is broken. But when you bring it down and have a closer look, you’ll see how many are defective. Do not forget to replace mounts with minor cuts on them.

Straighten or replace bent axle: A car axle is an expensive component. If you suspect a bent axle, take your vehicle to a mechanic shop for a fix. They can either straighten or replace it.

Replace bent driveshaft: Driveshafts hardly bend unless there’s a significant impact during a collision. The problem with these components is the spicer bearing on the joints. These components do not last the life of a vehicle. Hence, they are bound to fail. When they fail, get new ones and replace them.

Replace torn vacuum hoses: A straightforward fix to this problem is to track where the leak is coming from and reconnect or replace the hose.

FAQs

Q: Why does my car shake at 70 mph?

There are several reasons for a vehicle to shake at 70 miles per hour. It could be uneven tire wear, unbalanced tire, worn-out driveshaft bearing, faulty brake components, and a host of other reasons.

However, unbalanced wheel tires are the common reason cars shake at high speeds [within 70 mph and above]. These tires usually have a scalloped or cupped wear pattern on them.

These issues usually occur after replacing new tires. It also happens after hitting bridge expansion joints, potholes, and curbs.

Vibrations on the floor and seat are signs of unbalanced rear wheel tires, whereas vibration on the steering wheel signifies unbalanced front wheel tires.

Q: What does it mean when your car shakes at a certain speed?

The common reasons vehicles shake at certain speeds are traceable to imbalanced tires, suspension issues, loosed steering components, and engine or brake problems. Sounds like the reasons are much, right? The above sections have detailed the cause of the vibration at various speeds and how to fix them.

Q: Can a bad alignment cause a shake?

Vehicle suspension system components work harmoniously to align the tires, helping them to meet different road pavement conditions. As the tire rides on various road pavements, over time, rough driving, road turbulence, and road hazards can cause the tire to go out of alignment. These can cause the tires to rest at skewed angles.

Back to the question, “can a bad alignment cause a shake?” Even the most minor alignment issues can lead to car shakes or vibrations. Besides the vibrations, alignment issues can cause uneven and accelerated tire wear. Alignment service can fix this problem and its symptoms.

Q: Why is my car wobbling?

Suspension issues and unbalanced tires most commonly cause wobbling vehicle wheels. They are ominous signs and can lead to collisions. If the wobbling is so clear that you can feel it on the steering wheel, and you find it challenging to keep driving in a straight lane, the vehicle can keep you stranded in the middle of nowhere. You need to visit a mechanic shop.

Several factors can cause a car to wobble. These factors include misaligned suspension, damaged suspension, loose lug nuts, and unbalanced wheels.

Q: Can a bad tie rod cause a shake?

One of the noticeable symptoms of a bad tie rod is car shaking or vibration sensation in the steering wheels. You will also hear rattling and clunking noise on the wheels, especially on low-speed maneuvers. 

These sounds show a failing tie rod. As the tie rod continues failing, they will break free and emit loud rattling noises. If the tie rod dust cover tears, it can also cause rattling noise, shaking, and vibration sensation. These signs show it’s time to inspect the tie rods and replace them if necessary. 

Q: How much does it cost to fix car shakes at high speed?

The cost of fixing car vibration at high speeds varies since several factors can be the culprit. If you are lucky, it’ll be something simple, like a wheel alignment or tire that requires balancing. It will require a few bucks to fix it.

If tire issues cause vibration on highway speed, $20 can fix it. Problems like lousy engine mounts will cost $200 to $600 to fix it. The actual repair cost depends on the cause of the problem.

Final words

Vibration at high speed is not good even for an old car. If a car shakes at high speeds, it shows an imminent problem in the vehicle. Do not think driving at a certain speed range will solve the problem. 

Instead, fix the problem the moment you notice it. Quickly inspect the outlined causes in this article and follow our guides to fix them. If you’re unfamiliar with the underhood working principles, seek professional help.

Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

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