Needle roller bearings have been in existence for some time. They help to reduce frictional force. Typically, they are can be used for lightweight or heavyweight applications. They play a huge role and they should not be ignored.

A rolling element bearing can either be a roller bearing or a ball bearing. Roller bearings are made up of needle, cylindrical, spherical, and tapered bearings. Of all the members of the roller bearing family, needle bearings are the smallest and lightest. This is why they are ideal for use in certain applications especially when reduced weight and space constraint is a consideration. Its length-to-diameter ratio is also relatively high and this is responsible for some of its characteristics. The features of needle roller bearings include:

  • It handles large and rigid shafts in certain applications
  • Its load capacity is greater than that of single row or roller bearings of similar OD
  • Its cost is reasonably lower
  • It rolls well even in tight spaces

Needle rollers

Full-complement loose needle rollers are the most economical type of needle roller bearings. It is often used in applications where the outer raceway is a hardened and ground gear bore. When fully assembled and applications are met, a small cross sectional bearing can be formed by a full complement of rollers. This bearing usually has a high load capacity. If you analyze its cost for each pound of capacity, it is the most reasonable and cheapest. There are different end configurations of needle rollers and it is used in applications such as planetary gears, U-joints, and constant-mesh gears

Drawn-cup needle roller bearings

They are relatively easier to handle and install. It has a case-hardened outer shell that doubles as the outer raceway. This outer shell is made from low-carbon strip steel. This bearing is highly economical because it does not require subsequent machining. It is used in applications such as pilot bearings, pulley support, gearbox shaft support, and gear pumps.

Needle roller and cage assemblies

It is a cage assembly design with several advantages. Firstly, it gives control over radial internal clearances. Also, it helps to ensure the load is appropriately distributed between raceways and rollers. Another advantage it has is that it does not tolerate misalignment of the shaft and it can operate very well in high-speed conditions. It is widely used in planetary gears, connecting rods, idler gears, and constant-mesh gears.

Heavy-duty needle bearings

Its outer ring is machined, thick, and well-grounded. It has the ability to handle overload and shock. The cross-section of the outer ring permits mounting in a split housing. It also has a cage that shields the rollers. Also, it has the ability to handle high speed and misalignment. It is used in the steering gear, heavy machines, and hydraulic pumps.

Thrust needle roller and cage assemblies

It has the ability to carry an axial load in limited spaces. It holds needle rollers with a hardened steel cage. Their load capacity is impressive and they deal with friction expertly. It can provide low friction in a limited amount of space, and this explains why it is generally used in automatic transmissions.

Track rollers

It is often used on track-type equipment. It consists of a thick outer ring. This outer ring can handle shock loads and withstand heavy rolling which is common for such application. Mounting arrangement designs vary. Actually, there are two types. For a clevis mounting, you can make use of the yoke type. The integral stud type is ideal for cantilever mounting. Track rollers are used in applications like machine ways, cam followers, and mast rollers.


A needle bearing is a form of roller bearing.  However, its length-to-diameter ratio is on the high side. They are used in a wide range of applications such as farm and construction equipment, alternators, automotive transmissions, gear pumps, gasoline engines, tool motors, and aircraft controls. They can be lubricated in different ways such as the use of grease, oil-mist, and oil. However, if it is to serve heavy-duty or high speed purposes, it is better to use oil or oil-mist as the lubricant. Bearings used for light-duty applications do not necessarily need to be lubricated.

The rollers of needle bearings are literally the smallest of all roller bearings for a particular bore size. Also, of all rolling element bearings, their load capacity is the greatest considering a specified radial space. However, they are not often used for bore diameters that exceed 10 inches.

Needle bearings are available in two design patterns. The first pattern is a full complement which means it does not have a retainer. The second has a retainer and it is called a caged needle. The role of the retainer is to ensure spacing and roller guidance. The load capacity of a caged bearing is less than that of a full-complement bearing. Also, its roller complement is way smaller. On the bright side, a caged bearing has a higher speed capacity than a full-complement bearing. Furthermore, the fact that cages bearings have retainers helps to ensure there is effective roller guidance. Also, their lubricant capacity is way superior.

A loose needle bearing is basically a full complement of needles that found in the middle of machine components. It forms the raceway of the bearing. They are easily be misaligned. Also, they make it possible for an inexpensive and sensitive bearing assembly that has moderate speed capability to be created.

The caged assembly acts as a raceway and it is often positioned between hardened machine components. It is a roller complement that has a retainer. They have greater speed capability than loose needle bearings. In fact, it is three times that of a speed bearing.

A drawn-cup full complement bearing is made up of a full complement of needles and a deep-drawn cup which is the outer race. The needle may either be retained by the cup lips or grease, depending on the design. This grease-retained bearing has a greater load capacity.

There are few-dimensional similarities between a drawn-cup caged bearing and a full-complement bearing. The only difference is in the use of a retainer. The retainer helps it to operate at a faster pace and reduced load capacity. However, the full complement bearing is not as tolerant as the caged bearing.

The outer ring of a heavy-duty bearing is slightly heavier. This ring is often made from materials that are hard and precise.  They also have a high load capacity.

A cam follower can also be called a track follower. It is a needle bearing that can withstand heavy-duty application. It can have features such as eccentric-mounted studs, self-lubricating rings, heavy-duty studs, coatings, and platings.

Aircraft bearings are suitable for heavy-duty applications. They can operate under diverse conditions whether static, oscillating, or slow rotation. It can either be a single roller or a double roller. The single roller aircraft bearing does not compensate for misalignment while the double roller type does. Both types have oil holes and grooves that help keep the unit lubricated. A thrust bearing is a form of caged bearing. However, it has rollers and these rollers are properly assembled. A thrust bearing can operate under a fairly high speed condition.


The use of wheel bearing did not start today. They have been in existence for a long time. Their existence is almost as old as a wheel itself. A wheel bearing makes it possible for a wheel to rotate freely without the interference of friction. In this article, we will be looking at some of the parts that make up a wheel bearing. We will also be taking about the differences that exist between various bearing types.

Types of bearings

Ball bearings: They are round and metallic. They can be found in a wide range of applications such as bearing assemblies of a vehicle, electric motors, skateboards, and some household equipment. Ball bearings handle different load types (radial and thrust) because their shape permits them to spin in different angles. However, their contact area is very small and this means they are not suitable for heavy load applications.

Straight roller bearings: They are cylindrical in shape. They are also characterized by uniform diameter across the board. Unlike ball bearings, they are perfect for heavy-duty applications. This is because they allow the radial load to be spread across a wider contact point. However, they are not able to handle thrust load because of their shape. An example of where straight roller bearings are used is a gearbox since it has a tight space.

Tapered roller bearings: The shape of this bearing type is also cylindrical. However, its side is tapered. Tapered roller bearings are able to handle thrust loads, radial pressure, and hard shocks expertly. They are commonly found in the wheel bearing assembly in wheel hubs. It can be used as a single entity or in pairs, with each one facing opposite directions.

Some bearing assembly components

Race: It is a ring-like component made from metal. Races have inner and outer surfaces. It creates a surface for bearings to rotate against. If the bearing assembly is new, a race will likely include but you’d have to check to be sure. If it is absent, you will have to purchase it separately. Avoid the temptation of using an old race with a new bearing no matter how well it looks.

Bearing cage: This is a form of race that is characterized by perforations. It creates an inner surface for the bearing to rotate against. They are sold together with bearings since they are not separated from the assembly.

Bearing seal: It is usually round with an O-shape. It helps to protect the bearing assembly from moisture and grease. It can be bought separately in case it is not included in your new bearing assembly purchase. There are sometimes referred to as bearing retainers because of the role they play.

Bearing snap ring: It is metallic, rigid and circular in shape. It does the job of keeping the bearing assembly in position by clipping it. It can be removed or installed by making use of a snap ring removal tool.

Wheel hub: This is a piece of metal that an automobile is mounted upon. It is embedded in a wheel hub where it permits rotation without restriction around a spindle or an axle shaft. A wheel hub bearing assembly is one that mounts inside a wheel hub. The features of a wheel hub bearing assembly depend on individual manufacturers. Some are made with integral bearing assemblies and this means if a fault occurs, the entire wheel hub will have to be replaced.

Wheel hub/bearing O-rings: This is often found in older vehicles such as vans and 4×4’s. They provide a support and defense system against leaking grease from a wheel bearing assembly.

Bearing grease: This acts as a lubricant. It is synthetic or petroleum-based grease that helps to minimize frictional forces. It has a high viscosity and this allows it to remain thick and sticky even under high and extreme temperatures. This is a characteristic that distinguishes it from motor oil and gear oil. When working on a bearing, it is important to have clean grease on standby. If the grease has been left uncovered for some time, do not use it as it may have attracted dust and dirt. If you discover that the cover of the container that holds the grease has been compromised, do well to replace it.

Bearing grease packer: It has a center shaft and it is a perfectly shaped receptacle. It houses an O-shaped bearing assembly comfortably. When placed inside the packer, the bearing assembly stays on lubricating grease and as pressure is applied, it is immersed into the thick and viscous grease. After it is fully immersed, there would be no gap or opening between bearings, cage, and race. It is the most practicable way of ensuring most of the bearing areas are covered in grease. Applying another layer of grease on the bearing assembly after it is removed from a grease packer is a good practice.

Bearing dust cap: The job of the bearing dust cap is to prevent dirt from entering the bearing dust cap. It also ensures lubricating grease sinks into the bearing very well. Bearing dust caps are metallic and they can be pressed over the outer edge of a wheel hub bearing assembly.

Vehicular drivetrain

A bearing does not work the same way in a front-, rear-, and all-wheel-drive system. Often times, the variation depends on which of the wheels are drive wheels. In a drive wheel, the bearing is referred to as an “axle bearing” whether front- or rear-. This is because of where the wheels are mounted which is usually the axle shaft.

If it is front- or rear non-driven axle, the bearing assembly will be referred to as “wheel bearing”. Usually, they are mounted between a simple spindle shaft and a wheel hub. Four axle bearings are used in an all-wheel-drive system.


An automobile is made up of several components that interact and generate a great deal of friction. Often times, friction leads to the generation of heat. With a bearing, we can reduce frictional force. If there is no wheel bearing in a vehicle, the wheel will not roll. Instead, it will slide. When the sliding starts, the driver may find it harder to control the vehicle and its functionality is greatly affected. In this article, we will be letting you know the symptoms of a bad wheel bearing. We will also be discussing the features and importance of rear wheel bearings.

What is a wheel bearing?

Every wheel in the vehicle has a wheel bearing. A bearing may either be a steel ball or roller. It is usually covered in a metal known as a “race”. The spinning of the wheel leads to the generation of heat and frictional force. What a bearing does is to protect the wheels and tires by lowering friction. The wheel bearing is embedded in a hub assembly. The hub is responsible for holding the lug nuts which offers security for the wheels on the tires. A hub can move over different roads and handle a car’s weight.  It also helps the wheel to work well as it spins continuously.

Unbearable bearings

Wheel bearings wear out after traveling several miles. The wear and tear of the wheel bearing is caused by perpetual revolution and the heavyweight of the vehicle. This makes it harder for the wheel to roll as much as it should. Recently produced wheel bearings are sealed and this prevents moisture and debris from affecting it. The sealed wheel bearing is difficult to maintain as it cannot be cleaned or serviced. If the bearing is worn or bad, it has to be replaced out rightly along with the hub.

How do I know that a wheel bearing is worn?

When a wheel bearing stops rolling, heat generation increases, and frictional force will rise. This makes it harder for the vehicle to be controlled. In fact, the vehicle may become shaky and this is not safe. If you notice any of the under-listed symptoms, it means you may have to replace your wheel bearing.

  • An unusual sound: If the wheel bearing is not able to roll the tires as well as it should, it creates noise (a grinding sound). This noise is often amplified as the vehicle moves faster. It simply means metals are rubbing on each other.
  • Steering wheel shakes: The wheels of the steering will be unbalanced even if you move at a low speed. It needs to be attended to as quickly as possible, otherwise, it will get worse.
  • Tire damage: If the wheel bearing is bad, there would be a need to replace the tires of the vehicles frequently. A faulty wheel bearing causes misalignment of the vehicle. A worn tire is unsafe, especially in bad weather.
  • Unpleasant driving experience: This is the overall effect of a bad wheel bearing. It makes driving a lot more difficult and it can cause an accident.

If you notice any of the aforementioned signs, call a mechanic or technician. It is very unwise, risky, and hazardous to drive with a bad wheel bearing. The role a wheel bearing plays in an automobile is a delicate one. It helps to ensure that the wheel is attached to the vehicle. Traveling at a high speed or on a highway with a bad wheel bearing could lead to loss of control of the vehicle which can cause an automobile accident or loss of life.


With a roller bearing we can create low fiction movement for a bearing block. Roller bearings are usually cylindrical in shape. On the other hand, ball bearings are spherical in shape and are used in a similar fashion to roller bearings. The dichotomy between both bearing types is in the contact surface between the rail and bearing. The contact surface for a ball bearing is usually a single point as long as the bearing is perfectly spherical and there is no deformation. Even if there is a little bit of deformation, there is only going to be a limited space between the rail and bearing. The effect of this is that the balls will have an inherent limit of strength. Unlike ball bearings, the contact surface for roller bearings is a whole contact line. This makes it very rigid and stable. It also enhances the system’s maximum load capacity.


Smooth driving is made possible because of the collaboration between wheel bearings, tires, and hub. A faulty or absent wheel bearing brings about an increase in friction and ineffectiveness of the wheel. When a wheel bearing is faulty or absent, there are a few warning signs to lookout for. Let us look at some warning signs and safety concerns of a bad wheel bearing.

  • A loud noise is the most obvious warning sign. This noise usually emanates from the vehicle’s wheel or tire. The sound is like a grounding metal and as the pace of the vehicle increases; the noise gets amplified. If you hear such a sound from your vehicle’s wheels, make sure you reach out to an experienced mechanic.
  • You could also confirm the condition of a wheel bearing from the steering. A loose or wobbling steering could mean the bearing is faulty or bad. This is a very dangerous situation because the responsiveness of the vehicle will be slow and poor.
  • A bad bearing could also make your vehicle tires wear out rapidly. This means you have to spend on tires almost every time. To avoid this situation, make sure you replace the wheel bearing as soon as you suspect or detect malfunctioning. This will help you save a lot of money that would have been spent on buying a new tire.
  • If a wheel bearing is not in top shape, it is better and safer not to drive the vehicle, especially on the highway. This is because the wheel may leave its position as the vehicle moves. A faulty wheel bearing means there isn’t an appropriate mechanism to attach the wheel to the car.

If you notice any of these signs, make sure you reach out to a mechanic. Doing this will ensure safety and reduce repair costs. It does not make sense to put yourself at risk.


There are two types of ball bearings – the ball type and the tapered roller type. Angular-type ball bearing is used in front wheel bearing applications. The reason is because it can cope with higher thrust load. A tapered roller bearing can handle load in different directions whether axially or radially. Cartridge-type wheel bearing set is often used in rear axles. This wheel bearing set contains of a tapered roller set or ball set.


The construction of a basic seal has not changed. The only tangible difference is the primary sealing material. The sealing material has switched from felt to rubber products. Felt is now used for a different thing entirely. It serves as a dust shield. Before installing the shield, make sure it is well lubricated otherwise, it will run dry. It also prevents cocking of the seal during the installation process. If the seal is to be installed over a splined shaft, ensure you make use of a shaft protector. It is also important to include the dust cap in the sealing system.

Wheel bearing adjustment

If a wheel bearing is misaligned, the life of the bearing is at risk and it can lead to the damage of some other components. Components like the spindle, brake, and wheel seal are also affected. Always make sure the ends of the wheel bearing are properly adjusted according to the spec. If it is too loose or tight, it can bring about bearing failure. Since the advent of disk brakes, the adjustment of a bearing has been crucial to the performance of a braking system. Mounted directly to the steering knuckle is a caliper. In fact, this is the norm in many modern vehicles.

Hub bearings

This is very popular with front-wheel-drive vehicles. Its popularity started in the 1970s. It is a unique bearing that is sealed and pre-adjusted. It is also properly lubricated and it is contains a mounting flange for easy linking to other parts and components. Hub bearings used in passenger cars and light trucks cannot be adjusted. Furthermore, this bearing can either be a ball type or passenger type. The condition of the bearing has a direct effect and impact on the state of the hub. A noticeable sign of defect is an unpleasant noise from the wheel immediately the steering is turned. There are different parts of a braking system but a wheel bearing is literally the most critical component even in complex Electronic Stability Control (ESC) braking systems. It does the job of making sure the rotor and wheel are properly aligned to the caliper. It also ensures proper positioning of the wheel and drum to the backing plate. Furthermore, it regulates what is inputted to the wheel speed sensor.

The importance of quality

Do not replace wheel bearings with inferior or sub-standard parts. If the performance of the replacement is not impressive, it can lead to damage of the vehicle. Apart from that, inferior aftermarket bearings may cause endplay problems. Ultimately, it can make the car useless.


If you do not press the inner race of the new bearing onto a shaft, it may be damaged. To avoid failure, do not hammer a bearing as this can cause the dimpling of the balls and rollers. To drive a tapered bearing cup into its position, it is okay to use an aluminum driver. There is also a special tool that can be used to press a bearing into a steering knuckle. With an electric hot air gun, we can successfully install a bearing into an aluminum steering knuckle. This enables us to expand the housing without causing damage to the metal.  

Making use of the right tool and following the appropriate procedure when installing a bearing assembly helps to guarantee safety and longevity.


There are different types of bearings and each of them has unique properties, qualities, and areas of application. The final choice depends on the qualities needed and where the roller will be used. In this article, our focus is on the cylindrical roller bearing.

The basics of cylindrical roller bearings

The name of a cylinder roller bearing gives an idea of its properties and how it is different from other types of rollers. Just as the name suggests, its main rolling element is a cylinder. On the other hand, the rolling element in a ball bearing is a ball. The length of this cylinder usually exceeds its diameter. The radial load capacity of ball bearings is lower than that of cylindrical roller bearings. Also, the design of ball bearings does not permit fast speed as much as a cylindrical roller bearing.

There isn’t just one type of cylindrical bearing. The most popular type of cylindrical roller bearing is the single row cylindrical roller. They are easy to mount and dismount. However, they do not have the capacity to support a heavy load in some applications.

If you want a cylindrical roller bearing that can transmit axial load in a single direction or handle a higher radial load, you may want to consider a multi-row cylindrical roller bearing. The clearance and lubrication option of a cylindrical roller bearing depends on the manufacturer or supplier.

Uses of cylindrical roller bearings

Due to the fact that they can accommodate fast load and high radial load, cylindrical roller bearings are used in diverse industries. Areas of application include:

Manufacturers of cylindrical roller bearings

There are so many manufacturers of cylindrical roller bearings all over the world. However, not all manufacturers have the same reputation. The quality of bearing depends on the materials used and the reputation of the maker.


A tapered roller bearing is made up of tapered raceways and tapered rollers. The raceways are inner and outer rings. It has the ability to handle a combination of loads whether radial or axial. At the bearing axis, the raceway lines converge to enhance rolling and lower frictional force. The magnitude of the contact angle usually determines how much the load capacity can be increased. If the degree of angle is high, the contact angle will be high and vice versa. To improve load handling, tapered roller bearings are usually combined, such as in the wheels of vehicles. They are also used in heavy-duty applications.

Uses of tapered roller bearings

They are found in a wide range of everyday applications such as vehicle wheels. Apart from the automobile industry, tapered roller bearings are also used in the farming and agricultural sector. They are used to support different types of axial load in different directions. Tapered roller bearings are also used in wheel and axles, railroad axles, propellers, engines and reducers, gearboxes, mining, and construction.

Advantages of tapered roller bearings

Tapered roller bearings reduce frictional forces and heat generated between components. The shape of the bearing makes it possible for the load to be transferred evenly. It also reduces wear and tear and enhances the durability of parts. This is why they are universally used in shafts and rotating axles. Tapered roller bearings do not require much maintenance and they are very durable. Their reliability also makes it possible for them to be used for heavy-duty applications.

Bearing- NUP (RIP, RP)

This type of cylindrical bearing is characterized by a double ribbed outer ring and a singly ribbed inner ring. It also has an abutting loose rib that enables the bearing to bear light load in different directions. The factors that determine the capacity of radial and thrust loads for the NJ type are the same as this. It exists in sizes ranging from 80mm to 2000mm.

It has so many design attributes. For instance, it provides axial location and carries light thrust loads in both directions. It also has an abutting loose rib and outer and inner rings.

It is often used in power generation equipment such as gear drives, gearboxes, and pulverizers. Furthermore, it has relevance in the cement making industry where it is used in equipment such as crushers, gear reducers, rotary kilns, pillow blocks, conveyor drives, and trunnions.