What is a wheel hub and how does it work?

Wheel hub is also known as hub assembly, hub bearing, car wheel bearing, and wheel hub unit. It is an essential part of automobiles, especially cars, light and heavy trucks. The primary purpose of a car wheel bearing is to mount wheel with the vehicle. Usually car wheel bearing is located between the drive axle and discs of brakes. It is important to tighten the car wheel bearing properly according to the specification of that particular vehicle to prevent any kind of risk of failure. SKF is a popular name in bearing manufacturers for automobile and they have extended their services and technologies to hub bearing replacement, too.

SKF now designs and manufactures car wheel bearings and other integrated components for vehicles. These hub bearing replacements tend to have a long life and ability to deliver high performance even under extreme conditions. The company is specialized in developing car wheel bearings and other relevant parts with high load capacity and these parts are built according to specific specifications of the application. Some of the wheel hub function specifications include load capacity, stiffness, performance and well as durability.

 

What is a car wheel bearing?

Car wheel bearings are essential part of vehicles as they allow them to function properly and deliver performance even in harsh conditions. Car wheel bearings carry the load of wheels in smooth way without increasing the friction as well as provide them surface that helps them turn while cornering. As wheel hubs not only bear the load of vehicle all the time but also face heat, friction and other extreme conditions, they frequently require hub bearing replacement.

Earlier it was easier to perform a hub bearing replacement, but now they come as integrated part of the assembly that makes it difficult to do a hub bearing replacement without proper tools. Additionally, ABS sensor is also part of the assembly, and if it gets faulty or damage the entire assembly must be replaced.

SKF Wheel Hubs

The company designs wheel hub with some other features and components like bearings with relatively higher contact angles and higher shoulders to provide ability for sharp turns, high load capacity, specially designed seals for lowest possible friction and specially made grease to operate under high temperature and load. SKF develops these apparatuses to meet the demands of ABS to ensure the vehicle has sharp cornering capabilities.

SKF manufactures wheel hubs for hub bearing replacement with built in sensors for ABS with light weight components to take the full advantage of the technologies. The company manufactures four different types of wheel hub bearing replacements which come with different capabilities and characteristics. The conventional type is not only has complicated mounting and installation process but grease packing is required too that is also a hard work. HUB one is relatively easier to mount and install as compared to conventional type and there is no grease packing required. It also comes with compact design and seal.

HUB two has easier to configure preload settings as compared to HUB one and there is an option to install sensor rotor in this type. HUB three needs no manual preload configurations and it comes with high rigidity too. Other than that, this type also has easiest installation process of ABS sensor. The company makes wheel hubs with different types of bearings and specifications according to the requirements and applications. Hub unit bearings with angular passive sensor have compact size and it is more reliable because of the seals that protect sensor. Hub unit bearings with integral sensor located between the rows have compact size that is achieved by utilizing space efficiently.

How to spot a faulty wheel hub?

Unlike the symptom diagnosis, it is very easy to spot if a bad wheel bearing is dangerous or faulty with a simple test. A tire should have no or very little play. The play is defined as the degree of movement a tire or wheel hub can have. If there is unusual play in tire then it is probably because of faulty wheel hub that should be replaced immediately. The same test can also determine whether the wheel bearings are fine or they need to be replaced. In order to conduct this simple test you only need an auto jack.

Raise the wheel using the auto jack and only a few inches are enough, you don't need to go under the vehicle too. Support the car with jack stands and grab the wheel from 6 and 12 positions. Now try to shake the wheel and try to feel if there is any play. There should be no movement and if there is then either your car wheel bearings are faulty and you need to replace your car wheel bearings or worse the wheel hub is damaged and you need a hub bearing replacement immediately. No movement means the wheel hub and car wheel bearings do not need immediate replacement but you can conduct and additional yet simple test to determine whether they are damaged or not.

Put the vehicle in neutral or out of gear and rotate the wheel slowly. Try to listen to any kind of unusual sound, if there is some kind of noise that shouldn't be there then your vehicle might need a thorough diagnosis from a professional. Besides noise, there could be some roughness if there is something damaged inside the wheel. Make sure you put the car in gear or parking before lowering it down. Remember, these tests determine some common faults and issues associated with wheel hubs and wheel bearings, even if there is no play and roughness, wheel hub might be faulty.

Wheel Hub and Bearing Failure Dangers

Wheel bearings are small components as compared to the whole vehicle but you will be surprised to know how important they are and how a malfunctioned wheel hub or wheel bearing can put your safety in danger. Additionally, it can also damage the important and critical parts of the vehicle or can put negative impact on the engine that may lead to reduced life or performance of the vehicle. Wheel hub and wheel bearings should be inspected and checked regularly to reduce this kind of risks.

If your ride is not smooth, you feel the vehicle is shaky, you hear unusual sounds coming out from the vehicle or you feel the car is not fully in your control then the issue must be further diagnosed. There are virtually unlimited reasons and caused of wheel hub or car wheel bearing failure. It could be caused by dirt, oil or moisture while extreme driving or frequent sharp cornering can also cause apparatus failure. If the wheel bearing or wheel hub is partially cracked or damaged then you will experience trouble driving and these damage parts with also put negative impact on other components.

But in some possible cases, if the wheel hub or wheel bearings fail completely then they might put you in a dangerous situation as the vehicle can go out of control any time. A completely failed or damaged wheel hub can damage the brake drums or discs that mean you will be in a free fall like situation. The ABS sensor that tells the system about the movement of each wheel is placed in the wheel hub. ABS control system determines the brake required and it controls the braking system of the car.

As you have anticipated already, the braking system of the car depends entirely on the ABS sensor and if the sensor fails or gets damaged then it will put your safety in jeopardy. A malfunctioned or damaged wheel hub can also damage the ABS sensor. Traction Control System also uses the same sensor to determine the movement of each wheel to provide full control of the car to the driver. You can consider TCS a subsystem of the ABS as both of these systems and their components work together.

Symptoms of a bad wheel hub

Some drivers can be sensitive to the noises they vehicles make and usually this is a good thing as unusual noises could be a sign of problems the vehicle has been facing. Although these noises start with low point but they might damage the engine or other important parts severely. One of the most common and alarming noise that vehicles produce is the noise coming from wheel hub, for safe driving you should maximize the performance and stability of your car by checking its wheel hubs and car wheel bearings frequently because a faulty or damaged wheel hub might lead to something serious without hub bearing replacement.

Unfortunately it is not that easy to diagnose all kinds of problems that might occur and this difficulty leads to damage to some parts of the vehicles without driver acknowledgment. Luckily, drivers can learn about all the symptoms of a bad wheel hub to minimize the risk of damage, it is also important to not ignore even tiniest fault or symptom as it might lead to something bigger in the future. Let's talk about some bad wheel hub assembly symptoms.

Malfunctioning of ABS Sensor

This is a common yet most ignored symptom of a faulty assembly or hub. The wheel hub or at least the bearings need to be replaced if the ABS sensor is not working properly. ABS sensor is used to determine the speed of car and if it is showing light on the dashboard then it means either there is an issue with the sensor itself which is possible but unlikely or the wheel hub is damaged.

Noise coming from the wheel

Noise coming from a wheel is definitely a sign that something is not in ideal condition in the wheel. Now, there are many different parts of the wheel that can cause an unusual sound but regardless of the fact the wheel hub is damaged or not, you must address that issue immediately. Sometimes damaged or worn bearings make that sound, sometimes the noise is made by bad wheel hub or it might be caused by misaligned wheel too. The sound can be very loud or can be like humming but generally wheel bearing noise is danger and there is something wrong.

Snapping, clicking or popping

Sometimes a bad wheel hub causes unusual sound while turning or during acceleration or deceleration. If you hear clicking, snapping or popping only during making corners then it might be due to worn bearings or faulty wheel assembly. On the other hand, if there is a grinding sound then it is definitely because of bad wheel hub and it must be replaced immediately.

Excessive vibration in tires

Wheel bearings are sealed with proper lubrication in them and if the seal breaks, the grease which is used as lubrication to reduce friction may come out and contamination like dirt and moisture can damage bearings. Without proper lubrication, wheel bearings produce noise as well as rough riding that can damage wheel hub too. Damaged wheel bearings can easily damage the wheel hub and the issue must be addressed properly as soon as possible.

Shaky or loose driving

If you feel the vehicle is not fully in your control and it is shaky then it could be because of faulty wheel hub requiring a hub bearing replacement. Bad bearings can also make your car shaky even at lower speed because damaged bearings loosen up and also loose wheel hub that creates this kind of situation.

Spherical Roller Bearings

Spindle Bearings

Thin Section Bearings