When your car shakes just after you hit the 60 to 70 MPH mark is an experience that you don’t want to happen, especially if you are in the middle of the freeway. If this ever happens to you, it’s crucial that you remain calm and carefully shift lanes, where you can drive at a much slower speed. Afterwards, find time to have your car checked because ignoring the issue may only lead to complications.

In any case, why would a car even shake or vibrate violently at such speeds? This incident may happen due to several factors, which may range from unkempt engine components to worn-out suspension parts. Generally, the whole issue boils down to the current condition of the components of your car as they can be subject to misuse. In this case, you will be wise to address the matter in the soonest time possible.

Factors That Cause Cars to Shake Unexpectedly

As mentioned earlier, there are different factors involved with this issue. Most of these automotive concerns are interrelated because they originate from the same problem. Regardless, each matter should not be left unattended or unchecked to avoid complications later on. These top 5 factors that contribute to sudden vibrations in a car are as follows:

  1. Wheel Alignment Issues

Wheel misalignment is one of the common reasons why a car vibrates, especially when driving anywhere from 60 to 70 MPH. Often, this problem manifests in the form of sudden vibrations from the steering wheel. Apart from that, the other symptoms of wheel misalignment that may cause the car to vibrate are as follows:

  • Off-Centred Steering Wheel 

Generally, a vehicle with wheel alignment issues would have problems with certain parts of its suspension. In most cases, however, this concern could loosen the steering wheel, keeping the latter from returning to its correct position after making a turn. Thus, you end up with the wheel being off-centred all the time. 

  • Tyre Cupping

As a result of wheel misalignment, the tyres could lose their roundness because of the tiny dents accumulated on their surface over time. Cupping may not just compromise the structural integrity of the tires but also affect their overall performance. Eventually, this issue could lead to different complications, fuel economy being one of the primary concerns. Another is the unexpected vibrations on the steering wheel.

  • Uneven Tyre Wear

This concern requires a straightforward approach. You need to inspect the treads on your tyres and assess if one side appears to be more worn out than the other. Tyre wear can be attributed to two factors: camber adjustment and toe adjustment issues. The former can be described as worn-out patterns on either the outer or inner edges of the tyres, while the latter as scallop- or feather-shaped patterns.

The other signs of wheel misalignment are squealing tyres and pulling or drifting—or when the vehicle gradually steers to one side of a straight road even without you controlling the steering wheel. Furthermore, while these tyre concerns may not be the direct upshot of misaligned wheels, they are all nevertheless interconnected in such a way that one can be the cause and effect of the other. 

Wheel alignment may seem like a minor issue from the beginning. However, if taken for granted, this problem may progress into something even worse and affect your vehicle’s performance. For that matter, you will be wise to act on the matter immediately. Otherwise, it would be a bumpy ride ahead when you try speeding along the road. 

  1. Problems with the Brake System

A defective brake system could also cause the car to shake or the steering wheel to vibrate. Typically, a warp in the brake rotor could trigger the latter. One tell-tale sign that you are dealing with this issue is a wobbling sensation when you apply pressure on the brake pedal. 

A corroded or rundown brake calliper may also cause the car to shake. This would become apparent when the car reaches speeds of 50 miles per hour or more. Additionally, you may also smell something burning when you stop the vehicle. 

Important Notes:

If you suspect a warped brake rotor, you can troubleshoot this issue by dismantling the front tyres of your vehicle. Before doing this task, make sure you have the proper equipment: a pair of gloves, a lug wrench, a jack, a straight ruler, and a brake cleaner. After loosening all the lugs with the lug wrench, lift the car an inch with the jack. Afterwards, unscrew all the lugs so you can remove the tire to expose the brake rotor. 

Use the brake cleaner to remove the rotor of rust and dirt. Once cleaned, place the edge of the ruler against the rotor. Look for any discrepancies on the surface of the brake rotor, such as gaps or bumps. The absence of any gaps or bumps means the rotor isn’t warped. Perform the same procedure on the other tyre to ascertain that the rotor is in good condition.

  1. Worn-out Suspension Components

Faulty strut or shock mounts can cause the car to vibrate when you drive anywhere from 50 to 70 MPH. Apart from that, you might also experience issues like poor handling, uneven tyre wear, and steering problems, particularly if left unattended. Extensive damage to the suspension mounts could affect vehicular performance. In such cases, it would be best to replace your car with a better suspension system. That’s because the cost of rebuilding the suspension might be the same as buying a more reliable vehicle.

Important Note: 

  • Radial runouts, or tyre feathering or cupping, can also cause suspension components to wear out. This issue is common in vehicles with wheel alignment issues. In that sense, not only are the tyres at odds when the wheels are misaligned, but it also causes wear and tears to the minor part of the suspension system. 
  • Suspension lift kits can also cause vibrations, especially if the U-joint is at an irregular angle. Usually, the shaking manifests when the vehicle performs a hard acceleration.
  1. Drivetrain/Transmission Problems

Faulty driveline components are also perceived as the primary culprits in case there are no issues with the wheels and tyres. While this concern may be prevalent among older vehicles as a result of gradual wear and tear, newer car models may also run into such a problem, particularly those that are constantly misused or neglected.

  • Damaged CV Joints 

In a CVT, when the inner joint shows signs of wear, it could cause minor vibrations, which may not be noticeable at first. However, the vibrations would eventually intensify over time, especially under hard accelerations, and that could lead to serious transmission problems later on. 

Typically, in such scenarios, the CV joint would have serious issues with the joint boot as a result of dirt and water reaching the grease inside this transmission component. Without proper lubrication, the constant metal to metal contact would result in immediate wear and tear. Resolving this issue would require a CV joint replacement. 

  • Damaged Axle 

Often, when we accidentally drive over potholes, curbs, or any object large enough to hit and scrape the underside of the vehicle, we would think everything is fine, especially when nothing feels unusual concerning your car’s performance. 

What most do not know is that even these accidents could lead to a bent axle.  The damage may be subtle at first, which is the case in most vehicles. Over time, however, when you try to accelerate, you will begin to feel the vibrations. 

  • Driveshaft Problems

Aside from the axle, a broken driveshaft is often the result of accidents. Driveshafts are a major component in a vehicle because they are responsible for delivering power from the engine to the axles, which are then transferred to the wheels. 

If the driveshaft is broken, any minor acceleration would cause the vehicle to either shake or vibrate, and it only gets worse the more you accelerate. Generally, a damaged driveshaft is often irreparable, so replacing it may be your best option. 

  1. Engine Concerns

Engines are the bread and butter of every automobile, big or small. These machines consist of several parts, each of which performs a significant role that allows the vehicle to run as smoothly as possible. If any of these components become worn out or fouled up due to neglect or mishandling, that may cause a car to shake or vibrate. Some of the factors connected to these instances are as follows:

  • Running Lean

Dirty or clogged up fuel injectors can lead to an uneven air-to-fuel mixture, which results in the engine being starved of fuel and oxygen. The same thing goes for dirty air filters. The incorrect air and fuel combination could result in the engine  vibrating mildly. Often, the mild shaking would intensify during acceleration. For that matter, keeping the fuel injectors free of clogs and replacing the air filters regularly is crucial in proper engine performance. 

  • Dirty Spark Plugs

Spark plugs are responsible for combusting the air and fuel mixture inside the engine cylinder. If a spark plug is fouled up, it tends to misfire, and that would cause the engine to rely on the remaining cylinders for power, which results in underperformance. When this happens, you will notice the car vibrate while you are driving. In such cases, you will be wise to replace the dirty spark plug at the moment’s notice. 

Important Note:

Since the engine is an important part of your car, it is wise to note that the engine oil deposits and the improper fuel octane also cause the car to shake or vibrate. For that matter, taking care of your engine by changing the oil when necessary helps reduce the instances of engine vibration.

As for the latter, always be mindful of the fuel octane variant that you use for your car. Having the wrong one would not only cause your car to shake, but it would result in a high consumption rate and poor engine performance. 

Final Takeaway — Car Shaking When Reaching 70 MPH

Your best solution when your car shakes while driving at high speeds is to enlist the expertise of an experienced mechanic. Since the culprit could be any one of the components in your vehicle, a highly skilled technician can point out the problem with ease. Also, they can provide the necessary repairs and do it correctly the first time around, which reduces the chances of the issue recurring anytime in the future. Furthermore, with regular maintenance and correct handling of your vehicle ensures proper performance and lessens the likelihood of wear and tear.