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Visionary movies set against a technologically advanced future have long imagined that cars can drive on frictionless spheres similar to Star Wars' BB-8. We have not been there yet, because now cars still use wheels and tires to cope with the terrain, but without different types of balls, modern cars are impossible. We are talking about ball bearings.

Almost every new car has a set of miniature ball bearings behind each wheel, which can make the wheels rotate smoothly without interruption. They are unsung heroes when discussing the main components of a car, but their importance cannot be overemphasized.

Although these small balls are not part of the regular maintenance cycle, they will eventually deteriorate, so it is important to understand how they work when repairs are needed. For this reason, The Drive's reliable information team has gathered the answers to all your questions in one place. Let's explore it.

Wheel bearings are small metal balls mounted in a small ring, designed to reduce rolling friction and allow the wheels of the car to rotate freely, while maintaining the weight of the vehicle.

The wheel bearing is located in the hub and connects the wheel to the axle. Each wheel has its own set of wheel bearings.

The bearing is located in the hub assembly.

The two most common types of wheel bearings are ball bearings and roller bearings. One type of wheel bearing uses rollers, which are basically a series of small cylinders placed in a tapered circular housing. Roller bearings are usually not sealed, which is good for service, but is not good for susceptibility to contamination. 

However, ball bearings use miniature balls with small contact points to facilitate rolling. Ball bearings are usually sealed, which is very useful for preventing contamination, but they are usually not repairable.

The service life of wheel bearings depends on the manufacturer, daily operating conditions and driving load, but they are generally expected to last at least 75,000-100,000 miles.

The advantage of a wheel bearing is that you will know when it goes bad, thanks to some obvious symptoms. These are the signs you need to check: 

The most common symptom of broken wheel bearings is that they make strange noises when something is turned off. You may hear buzzing, whirring, rumbling, rubbing, or clicking, depending on how the wheel bearing is malfunctioning.

As the ball bearings wear out, they will start to loosen within their housing and/or lose some effectiveness. Therefore, the tire may wear unevenly. 

No, the steering wheel itself will not feel loose, but the steering feel may. If the bearing is broken, it may create some clearance in the wheel assembly. If this happens, your steering may feel more blurred than usual. 

If the wheel bearing seal is damaged and the inside is contaminated with hard particles, or if it just wears out over time, it may cause rougher driving and vibration than usual.

Most modern wheel bearings are sealed, for good reason. If any dirt, debris or other contaminants enter the bearing, it may reduce lubrication and increase friction. If it becomes too hot, or there is too much debris in the bearing, they may start to lock or grind. If the bearings lock up, the wheels may lock up.

Almost all new wheel hub components are equipped with built-in sensors that can notify traction control, ABS, stability control and other driver assistance systems. If something in the wheel bearing does not work properly, it may cause the system to malfunction, or throw out codes and warning lights.

Replace the entire wheel hub assembly to replace the wheel bearings.

The best way to deal with a bad wheel bearing is to replace it, together with other bearings to ensure even and balanced driving. Wheel bearings often appear as part of larger wheel hub assembly packages.

Every car is different and may require different steps, but these are the general steps that will be performed when disassembling the wheel hub assembly. 

Note 1: When replacing the wheel hub, you may need to use an anti-seize device to prevent future problems.

Note 2: After everything has been removed, now is a good time to check the suspension and brakes. 

Note 3: If one bearing is replaced, other bearings should be replaced.

The hub assembly is usually very difficult to disassemble. If you are already at work but do not have a drawing tool, these other tools and methods may be helpful. Please be extra careful not to damage anything and always take necessary safety precautions.

You have a question, the drive has an answer!

Answer: The only simple way to check for bad wheel bearings includes some assumptions. First, you want to hear strange sounds from suspicious wheels, such as humming, whirring, or rubbing. If you hear some sounds and can identify the source of the wheels, you can lift the car and check whether the wheels are moving, slack or playing a role in the linkage mechanism with the car. You can do this by grabbing each side of the wheel and moving back and forth or left and right.

A. The car may be able to drive, but we do not recommend driving with poor wheel bearings. If you notice symptoms and suspect bearing damage, please drive home or go to a repair shop immediately.

A. In one of the worst cases, the wheels may lock up while driving. In other words, driving with poor wheel bearings can be very dangerous.

Answer: Depending on the car, the average cost of a single hub assembly (not just the bearing) may be between 100-300 US dollars. If you do this yourself, multiply it by the number of hubs you want to replace. If you bring it to the garage, multiply that number, and then add labor costs. It will not be cheap.

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Jonathan Klein: Twitter (@jonathon.klein), Instagram (@jonathon_klein)

Tony Markovic: Twitter (@T_Marko), Instagram (@t_marko)

Chris Teague: Twitter (@TeagueDrives), Instagram (@TeagueDrives)

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