Car Shakes When Driving Over 70 MPH (Causes, Fixes & Cost)

‍Causes Of Car Shaking When Driving Over 70 MPH

As a mechanic in a tire shop, I get this question brought up quite a lot. Lots of people experience shaking at highway speeds. The problem is quite common, but can be quite worrisome to those who experience it. But do not worry.

I’ll go over some causes and concerns as to why your car shakes when driving at highway speeds. The first I check when a customer comes in with this problem is out of balance tires. Out of balance tires are the main reason a car would shake when going down the road at 70 miles per hour.

This is because when tires are out of balance, they start to violently hop down the road as you drive. This hopping translates to vibrations felt through the steering wheel and throughout the whole vehicle. So I’d take the tires off, and put them and an off car balancer. If the tires balanced out, I’d continue looking for issues.

The next thing I’d look for is for tires with uneven tire wear. Uneven tire wear is a sign there’s a wheel alignment problem. I see a lot of customers come in with wheel alignment issues that have shaking when driving at highway speeds. This is because the tires are being dragged down the road at an angle.

This phenomenon can also cause tire hopping which can translate into those nasty vibrations we’re trying to get rid of as well. When the wheel or tire assembly isn’t properly aligned, the car vibrates,  because the tire is being driven down the road at an angle causing it to hop.

Sometimes, I see plain ol’ tire issues being the cause of car vibrations. For example, if I see tires are properly maintained, I know this can translate to car vibrations. I like to see the tire pressure set correctly on tires and if I see the low tire pressure on one of the tires, I know this can be the cause of tire vibrations.

Brakes are the next thing I would check since sticky brake calipers can cause a car to vibrate. Sticky brake calipers can work against the momentum of the car, causing the brake pads to apply intermittently.

This intermittent braking can make the car feel like it’s vibrating. If you feel vibrations in your brake pedal when you are slowing down from highway speeds, I’d take the wheel assembly off and check your brake calipers and check for a faulty brake system . Next, I’d check the engine compartment.

Sometimes, the engine compartment holds the answers to all your problems. Spark plugs and fuel and air filters can sometimes be the answers. These items can cause problems for your vehicle’s engine. Not only can they cause problems, they can also cause car vibrations if they are causing misfires in your engine.

If you are experiencing a misfire vibration, which feels like a vibration in your steering wheel, pop the hood and pull these items out. Check for fouling of the spark plugs, dirt in the air filter, and a fuel smell around the fuel filter. These are the symptoms to look out for if one of these items has gone bad.

Lastly, a wheel bearing has the potential to cause steering wheel vibration. If your steering wheel shakes, it could be the wheel bearing. The front wheel bearing is connected to the steering wheel, so a growling wheel bearing will cause your steering wheel to vibrate.

Fixing And Cost

The cost to fix this issue can be a little or it can be a lot depending on what the issue is. If the issue is one of your steering rack components,  like a ball joint, wheel bearing, or brake component, I’d usually charge anywhere between $200 - $500 dollars.

If I see the issue is just having a wheel balance out of whack, I, or the shop, would usually just charge $11 per tire totalling around $50 bucks to balance all four.

If I see the tire is damaged and the tire has shifted or broken belts, you may have to purchase new tires, which can range anywhere between $400-$1200 dollars depending on the brand of tire you purchase.

If I see that you need a brake caliper service, this usually makes the bill rise quite a bit, since brake calipers can be between $150-$300 dollars for the parts alone. Wheel bearings and their replacement usually cost around $300 dollars since sometimes you need a press to put them in.

If the tire looks low on pressure, and I hook the tire pressure gauge up and confirm that it’s low, I will fill the tire up free of charge.  A shaking car can also be caused by engine sludge. Engine sludge will throw the engine out of balance, causing a car shake. To remedy this issue, I’d charge around $300 dollars, since cleaning the engine is quite cumbersome.

Making Sure You Don’t Get Ripped Off

You can always consult a repair manual to make sure the mechanic you are using isn’t ripping you off. It’s called book time. Book time is the time it’s supposed to take a mechanic to do a job. For example, the book time for a brake job on some cars is 1.2 hours.

If your mechanic charges around $60 per hour, you can do the math and see if you are getting ripped off or not. Always ask what the book time is if the mechanic you are using seems untrustworthy. This keeps them honest and makes them stick to their original price point.

There is a book time calculator on napa.com which is really great. Just put in your car’s year, make, and model to and the tool will give you a standard book time for the job. Book time is a double edged sword for the mechanic. Because if the job only takes 20 minutes but the book says it takes 2 hours, the mechanic gets paid for 2 hours.

But if the job takes five hours and the book says it only takes two, the mechanic may try and charge you for five hours. So always check the book time when you bring your vehicle to an independent mechanic.

Dealerships are less likely to abuse book time, since more policies and procedures are in place.

Balancing Tires

Balancing tires is an important maintenance procedure that helps to ensure that your vehicle drives smoothly and handles properly. Without balancing tires, all cars would experience some type of serious vibrations.

Tire balancing was invented to stop vibrations caused from tires. Here are the steps to balance your tires:

• First, remove the tires from your vehicle and place them on a tire balancing machine.
• The machine will then spin the tire and measure any imbalances in weight around the tire.
• Based on the machine's readings, you will then need to add or remove weight to the tire to balance it.
• To add weight, small weights are attached to the rim of the wheel. To remove weight, the tire technician will grind away some of the metal on the rim.
• Once the tire is balanced, it will be mounted back onto your vehicle and tested to ensure that it is driving smoothly.
• Repeat the process for each tire on your vehicle.

It is recommended to have your tires balanced every time you have new tires installed or if you notice any vibrations or shaking while driving. Balancing your tires will improve your vehicle's handling, reduce tire wear, and increase the life of your tires.

Balancing tires usually costs around $11 bucks per tire. This includes the price of the wheel weights and the labor. Balancing your tires is a great way to stop any vibrations.