The Car Shakes When Driving Over 70 MPH — 13 Things That Could Be Wrong!

So, your car shakes when driving over 70 mph, and you are confused as to how you could find out the fix for it. But let us be of assistance in telling you that the fix is not attributed to a single problem, for there could be many things wrong with your car, leading to absolute wobbling.

Nevertheless, there’s no worrying for you ahead, certainly not when you are over to this guide, entailing everything you need to know why your car shakes when driving over 70 mph and how you can fix it.

That said, it doesn’t matter if you drove to your mechanic yesterday and had your car tuned. There are some subtle parts deep into the engine that wear out or act up to shake the car, and unfortunately, you need to cross 70 mph to be sure that it’s them and not anything else—from the collective list of problems mentioned below.

1. Your Tires Are Unbalanced

Unbalanced tires are the most common cause of a shaking car speeding up to over 70 mph. There could be anything causing the tires to lose their balance, from bouncing off potholes to driving off-road to drifting often, it could be anything.

As for how you’d be spotting the tires being unbalanced, there would appear a ballooned area over one of the tire’s surfaces or it could be the rim getting crooked off its circumference, which will tell you to visit your mechanic and get an automated inspection of the wheels’ alignment and balance.

We’d also suggest not balancing the tires on your own. You wouldn’t want to end up with an unbalanced pair of hands instead. Also, unbalanced tires are also known by the following terms—just to add up to your knowledge, so it doesn’t perplex you knowing you had unbalanced tires till driving to your mechanic and now you have:

• Misaligned Tires
• Worn out tires

The most appropriate thing to do when you are sure it’s the unbalanced tires causing your car to shake over 70 mph is to sense whether it’s the steering wheel vibrating or the rear floor, for they both imply different scenarios:

1. If it is the steering wheel vibrating, beware that the front pair of tires are unbalanced or worn out, which might have you replace the tires for a substantial sum.
2. If it is the rear floor vibrating, you’d have to replace the rear pair of tires, costing you more or less the same as those of the front wheels.

If you are not sure, looking for the following signs might help you be decisive with changing or replacing the tires:

• Tires screeching
• The car pulling to the right or left despite steering it straight
• It makes noise when steering your way

There could be more, guided best by your mechanic.

2. Your Brake System is Faulty or Rubbed Off

The pads and calipers, to be specific, in the entire braking system stop performing at their maximum potential. They may wear out, lose their grip over the discs, or clip them even tighter—either way, it’d have you pressing on the pedal hard, which may result in rubbed brake pads producing a burning odor, sniffed best after you stop or park the vehicle.

The best solution in this situation is to let your vehicle rest for a while, which would allow you to drive a couple of miles without setting fire to the tires. Still, to get a better idea of what brakes to apply more and what to avoid, you should pay heed to the following factors:

• Your car would shake more prominently upon braking if it is the front brakes acting up.
• Contrarily, if it is the rear brakes, you’d feel intense vibration in the brake pedal, intense enough to have you stop your car by the road.

It is to ensure the problem lies within the brakes and that you don’t keep hitting the brakes you should not. Once you have made it to your mechanic, do as they say. For a better grip, read the difference between disc and drum brakes.

3. Your Exhaust is Modified

At times, you may feel like upgrading your car for its sound, resonance, and depth, and this is where you neglect the opportunity cost of it, which is the wobbling. Whether you replaced the muffler with that of heavy roars or failed to align it right with the framework, you will witness shakiness upon reaching 70 mph, an inevitable outcome.

It is because modifying the exhaust piles up the buzz created by the acceleration and leads to the vibration that you may also take for wobbling. But that’s not wheel vibration, in case you mistake it for that, for it has an alike set of symptoms equally deceptive.

4. Your Car is Not Wearing Weights

 Cars produce vibration upon reaching certain limits and in this case, above 70 mph. These vibrations are so developing that driving your car may become tackling a dinosaur, which never calms down. So, to counter them, the manufacturers add weight onto the framework that doesn’t let you feel the vibration and make driving an enjoyable and comfortable experience.

These weights are often detached from the vehicle while modifying the exhaust, so you need to be careful and ask your mechanic to pay extra attention to them. It will make it easier for you to feel the performance of your car.

5. Your Engine is Hesitating

Alongside shaking, your car may also hesitate a bit—in a sense that you may feel jolts as if your car is running out of fuel or losing the current. The straightforward solution to this problem is to check on the spark plugs of your car and get them replaced if need be. If you keep delaying the inspection or replacement, your car would leave you with no choice but to extend a towing hand to every passerby car.

Moreover, ask your mechanic to inspect the fuel management system for clogging, as it is one of the most common causes a car hesitates while picking up the speed and a pointer that spark plugs are not the problem. While it may cause your car to shake, it would also put it at stake, another reason why this is worth spending an hour or two of your time.

6. Your Powertrain is Tired
   

This is one of the problems that disclose itself at the speed of 70 miles per hour or more. So, you need to be at that level of control to determine if your powertrain needs rest, and if that’s the case, you better park the car under shade and let it sit there as you occupy yourself with time-passing activities.

You may also hear weird noises when steering the car, which is an explicit sign signifying there is something wrong in the car, which needs attention or ultimately replacement.

7. Your Suspension System is Worn Out

If you feel that your car is shaking even when you have not reached 70 mph, you should consider a worn-out suspension system. It might not always be the case, but it’s the closest. The only way to get sure about this is to have a thorough check-up of your vehicle at your mechanic’s, and following their word, replace or rebuild the system.

However, there are more chances of your mechanic suggesting a complete vehicle swap, for the cost of replacing the suspension system would add up closer to that of the swap.

8. Your CV Joints Are Worn Out

Spotting and ensuring it’s the CV joints causing wobbling across the car is a tough nut to crack, for you need to accelerate above 70 mph and carry weight in your car. This way, you might hear a screeching noise or ostensible shakiness. In some cases, it might also be a neglected vibration that you can only hear once it develops into an intense version of it, and it’d happen instantaneously.

Also, it wouldn’t be a waste to check out your front axles if your car shakes when driving between 40 – 50 mph, for the acting up front axles might be the case.

9. Your Vehicle is Excessively Lifted

One cause of increasing vibrations in the vehicle is excessive lifting to increase the aesthetics or performance of your car. When you get your vehicle lifted, you expand the angle between U-joint and drive shaft, which is directly proportional to the shakiness or vibrations that you feel while driving.

To put it simply, the greater the angle between them, the more powerful the vibration will be. So, you must behave carefully when deciding on a lift. It is because where it makes the vehicle flexible and bouncy, it also costs you the comfort of driving.

10. Your Spark Plugs Are Carbonized

Having mentioned the role of spark plugs above, you can predict why they get carbonized. It ultimately makes them dirty or dark, disabling them from sparking the engine to start. When they fail to generate current, your vehicle starts hesitating or jolting, which soon takes the form of shakiness or wobbling. To become sure, you’d see sudden drops in the RPM needle and loss of power, i.e., you might have to start your vehicle again and again.

However, since there are multiple spark plugs in a vehicle, you don’t have to check them one by one—to see if they have a darker tip or not; examining only one of them would account for all of their statuses. In a nutshell, if one is dark, so would be the others.

11. Your Vacuum Hose is Disconnected

Air is a vital component for the combustion to take place in the engine, and it’s the vacuum hose or air pipe that supplies it there. So, when the hose disconnects from the system, the engine adds everything in abnormal quantities, which results in a similar performance of the car, most probably shakiness and wobbling.

Anyway, it doesn’t require a costly solution, for you only have to change the air filters, costing you a few bucks or less. And you should get them replaced from time to time, as suggested by your mechanic—spending small chunks is always better than letting go of the entire piece.

Not to forget, it could also be your fuel filters causing the shakiness, and for them, the treatment is different as their location varies on the vehicle make and model. All in all, it’d still require replacement.

12. Your Gasoline is High Octane

The engine of every vehicle is endorsed for a specific gasoline octane rating and filling the tank contrarily would not have very favorable results. You may argue that high-octane fuel offers more mileage and is less hazardous to the environment, but not every engine is compatible with it, which yields shakiness, vibration, and poor performance in the car.

Additionally, if you add high octane fuel into the engine, it might not always increase the mileage, in some cases, it would enhance the fuel consumption, bewildering you over the number of times you had a refill.

Or, on the contrary, here’s what will happen if you put regular gas in a premium car.

13. Your Driving is Extreme
    

If you drive your car as a driver of Formula One, shaking is what will happen, or might as well be the vibration. Not every car is designed to be drifted or accelerated roughly. We’d suggest you buy a new vehicle to fulfill your wild desires, but it’s not your current ride that would let you fulfill them. The same is the case with driving off-road in a formal ride, which will have the engine perform twice as powerful as it is designed to, leading to an absolute mess in the parts and ultimately shakiness.

Such activities might damage your car from many places that would keep adding to your maintenance budget and might also have you replace your car with a new one.

The Takeaway

At last, you might want an air pressure gauge to accompany you in your car, for low-pressured or flat tires are the most frequently occurring causes of car shaking, and with a gauge available, you could always check on the pressure. To level the pressure, however, you’d also need an air pump, which is one of the essentials to keep in the car alongside the gauge.

These were the most probable reasons your car shakes when driving over 70 mph. Still, if everything from the mentioned causes works fine, your mechanic stands out as the last chance.