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Car ball bearings are components of a car's wheel assembly that allow it to bear weight and move smoothly. They are used to connect the car wheel to the axle and allow a wheel to perform two vital tasks – rotate fluently and support the weight of the vehicle. Without ball bearings, a car would grind to a shuddering halt.
Ball bearings are usually made from steel or ceramic for strength and durability. They are shaped like little balls and are neatly packed inside the wheel assembly to separate two moving surfaces. Bearings are designed to withstand high temperatures and strain. They are amongst the hardest-wearing components in a car.
What Does a Car Wheel Ball Bearing Do?
A car wheel ball bearing is used to connect a wheel to an axle. They are positioned as a group of bearings that sit neatly next to each other inside a metal ring known as a race. Bearings allow a car wheel to rotate freely without experiencing friction. They are designed to perform two critical tasks - support the weight of the vehicle and allow the wheel to rotate freely with as little friction as possible.
When the car is in motion the bearing balls roll along inside the metal race allowing the wheel to rotate. The bearing assembly is lubricated with grease or oil to reduce friction and facilitate smooth motion. Wheel bearings are an essential component of any vehicle, without them a vehicle would be unable to move.
How Long Do Ball Bearings Last?
A car ball bearing typically lasts between 85,000 to 100,000 miles – equivalent to 136,000 to 160,000 km. However, the lifespan of a wheel ball bearing will largely depend on the type of bearing, the quality of the bearing, and the operating conditions it is exposed to.
Wheel ball bearings that suffer harsh operating conditions such as heavy loads, poorly maintained roads, and persistent high speeds will have a shortened lifespan. Other factors that can shorten the lifespan of a car ball bearing include inadequate lubrication, poor installation, and the presence of dirt or debris in the bearing assembly.
How Do Car Ball Bearings Get Damaged?
The main causes of wheel ball bearing damage are impact damage, overloading, poor installation, driving conditions, and the use of poor-quality ball bearings. However, even properly installed good quality bearings will fail over time. They have a limited lifespan and the factors listed below will eventually wear and damage the bearings.
Impact Damage
Impact damage is one of the most common causes of car bearing damage. Wheels striking potholes, speed bumps, and kerbs are common sources of ball bearing damage. These episodes increase bearing wear and shorten the lifespan of the bearings.
Overloading
Overloading a vehicle with excessive weight can damage wheel ball bearings. If the weight of the vehicle exceeds the recommended load of the bearings it can cause the bearings to deform and distort the bearing race. This is bad news.
Poor Installation
Poor installation is a regular cause of premature ball bearing failure. It's especially common when aged parts are used in the assembly such as bolts, split pins, and seals. When bearings are installed or repaired they should be installed with new accessories to maximise their lifespan.
Use of Low-Quality Bearings
Low-quality wheel bearings will fail prematurely. Bearings are under constant high pressure and need to be manufactured to the highest standards to function properly and withstand their substantial workload.
Contamination
Poor driving conditions can cause contamination that damages bearings – especially over time. If debris, dust, or water gets into the bearing assembly. This happens when water or mud squeezes past the seals and makes its way into the bearings.
Wheel Modifications
Certain modifications can increase the load on the wheel bearings and have a negative impact on their expected lifecycle. These include fitting wheels with wider rims, adding stiffer shock absorbers, and using tyres with reduced thread walls.
How Do You Know if a Car Ball Bearing Is Damaged?
Most manufacturers recommend an interval at which bearings should be replaced. This is usually dictated by the mileage clocked up by the vehicle. However, many of us tend to ignore manufacturers' recommendations and continue to drive our cars until we notice something has gone wrong. So, if you choose to ignore the recommendations – how do you know when the bearings need replacing?
The first thing you'll notice when a bearing gets damaged is an increase in vibrations. If a bearing has been damaged in a wheel assembly you will notice vibration in the steering wheel you drive. Other symptoms of damaged wheel bearings include steering wheel looseness, excessive noise, and ABS malfunction – see below.
Steering Wheel Vibration
The first sign that you have a problem with your wheel bearings is a vibration in the steering wheel. You will notice that the level of vibration changes as you change speed.
Steering Wheel Looseness
Damaged ball bearings can cause excessive looseness in the steering wheel. This can feel like the steering wheel is unresponsive.
Noise
Another sign of damaged car ball bearings is whining and growling noises. The noises change as you accelerate or turn the vehicle.
ABS Malfunction
The ABS system is integrated with the wheel bearing assembly. And when the bearings get damaged the ABS system can fail.
Can You Continue to Drive with Damaged Car Bearings?
If you notice any of the symptoms listed above for a damaged wheel ball bearing you should stop driving your car. While it is rare for a ball bearing to completely fail immediately after noticing there is an issue – it is still recommended you address the problem as soon as possible.
Car ball bearings are essential components that connect the wheels to the car, support the weight of the vehicle, and allow the wheel to rotate. You should not drive your car if the ball bearings are damaged. Doing so is a serious safety concern and could cause lasting damage to your drive-axle and steering assembly.
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How to Fix Damaged Car Ball Bearings
Damaged ball bearings need to be replaced by a professional mechanic. The job involves the use of specialist tools and an understanding of torque values for your vehicle. Ensuring damaged bearings are replaced correctly is essential for vehicle safety and performance. If your car ball bearings are damaged – get in touch with your local mechanic and make an appointment to have the vehicle dropped in and repaired.
Other Types of Car Ball Bearings
What other types of ball bearings are used in cars? Wheel ball bearings are just one example of the types of ball bearings found in a car. Here are some other examples.
Steering System Bearings
A car steering system uses ball bearings to support the steering column, reduce turning friction, and allow easy and smooth steering.
Engine Bearings
Ball bearings are used throughout a car engine in areas such as the camshaft and crankshaft to reduce friction and facilitate smooth movement.
Transmission Bearings
Ball bearings are used to support and guide the rotating gears in a transmission assembly to facilitate smooth gear changes while driving.
Water Pump Bearings
These bearings are used to reduce friction in the water pump, support the rotating impeller, and allow the pump to circulate coolant efficiently.
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