Roller Bearings vs. Ball Bearings - What's the Difference?

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Rolling-element, anti-friction bearings, either ball- or roller-type, provide a mechanical means of countering radial and axial loads in rotating and reciprocating shafts. This article will briefly describe both types, then cite some examples where one type might be selected over the other. To learn more about the different bearing types, consult our bearings buying guide.

Ball Bearings

A typical ball bearing consists of inner and outer raceways, a number of spherical elements separated by a carrier, and, often, shields and/or seals designed to keep dirt out and grease in. When installed, the inner race is often lightly pressed onto a shaft and the outer race held in a housing. Designs are available for handling pure radial loads, pure axial (thrust) loads, and combined radial and axial loads.

Ball bearings are described as having point contact; that is, each ball contacts the race in a very small patch – a point, in theory. Bearings are designed such that the slight deformation the ball makes as it rolls into and out of the load zone does not exceed the yield point of the material; the unloaded ball springs back to its original shape. Ball bearings do not have infinite lives. Eventually, they fail from fatigue, spalling, or any number of other causes. They are designed on a statistical basis with a useful life where a certain number are expected to fail after a set number of revolutions.

Manufacturers offer single-row radial bearings in four series over a range of standard bore sizes. Angular contact bearings are designed to withstand axial loading in one direction and may be doubled up to handle thrust loading in two directions.

Shaft and bearing alignment play a critical role in bearing life. For higher misalignment capacity, self-aligning bearings are used.

To increase radial-load capacity, the bearing carrier is eliminated and the space between the races is filled with as many balls as will fit—the so-called full-complement bearing. Wear in these bearings is higher than those using carriers because of rubbing between adjoining rolling elements.

In critical applications where shaft runout is a concern—machine tool spindles, for instance—bearings may be preloaded to take up any clearance in the already tightly-toleranced bearing assembly.

Roller Bearings

Similarly constructed as ball bearings, roller bearings have line contact rather than point contact, enabling them greater capacity and higher shock resistance. The rollers themselves come in several shapes, namely, cylindrical, spherical, tapered, and needle. Cylindrical roller bearings manage only limited thrust loads. Spherical roller bearings can accommodate misalignment and more thrust, and, when doubled up, thrust in either direction. Tapered roller bearings can manage significant thrust loads. Needle bearings, a variant of cylindrical roller bearings, can handle high radial loads for their size, and can be made as needle roller thrust bearings.

Roller bearings are available as full-complement designs and needle bearings almost invariably will be of this style. Needle bearings are especially effective with reciprocating motions, but friction will be higher due to roller-against-roller rubbing.

When using cylindrical roller bearings on shafts with angular misalignment, it is preferred to use two short roller bearings back-to-back rather than one long roller bearing.

Choosing a Ball or Roller Bearing

As a general rule, ball bearings are used at higher speeds and lighter loads than are roller bearings. Roller bearings perform better under shock and impact loading.

Ball bearings are usually sold as assemblies and are simply replaced as units. Roller bearings can often be disassembled and the roller carrier and rollers, or the outer or inner races, replaced individually. Rear-wheel-drive cars use such arrangements for the front wheels. The advantage of this design is that the races can be shrunk fit onto shafts and into housings to create permanent assemblies without risking damage to the rollers themselves.

Single-row ball bearings are standardized and can be used interchangeably among manufacturers. Roller bearings are less-formally standardized so a specifier needs to consult a manufacturer’s catalog to select one appropriate for the application.

Rolling-element bearings are manufactured with a certain amount of internal clearance. Any misalignment that merely nudges a ball out of position and removes this internal clearance should not have much effect on the life of the bearing. Roller bearings are more sensitive to angular misalignment. For instance, a ball bearing running at moderate speed with a fairly loose fit might operate successfully with angular misalignment as high as 0.002 to 0.004 in./in. between the bearing and shaft. A cylindrical roller bearing, in comparison, might be in trouble if misalignment exceeded 0.001 in./in. Manufacturers will generally provide acceptable ranges of angular misalignment for their individual bearings.

What is the difference between a roller bearing and a ball bearing?

A roller bearing is a cylindrical unit that is used to provide low-friction movement for a bushing or bearing block. A ball bearing is a spherical unit that accomplishes the same objective as a roller bearing. The real difference has to do with the contact surface between the bearing and the rail. For ball bearings (assuming a perfectly spherical bearing and no deformation), the contact surface is just a single point. Even once deformation is accounted for, the amount of surface where the ball is contacting the rail is limited. This creates an inherent strength limit for the balls. Roller bearings on the other hand, have an entire line of contact. This greatly increases the rigidity, stability, and maximum load capacity of the system.

Difference Between Roller Bearing And Cylindrical Roller Bearing

There are various characteristics of roller bearings and cylindrical roller bearings that makes them unique to be used for different applications and performing environments. To help you understand it in a better way, this blog covers how roller bearings are different from cylindrical roller bearings.

At first glance, roller bearings and cylindrical roller bearings may look quite similar. However, there are actually several key differences between these two types of bearings that can impact their performance. In this article, we will explore the key differences between roller bearing and cylindrical roller bearing so that you can choose the right type of bearing for your needs.

What Is Roller Bearing?

Roller bearings are a type of bearing that uses rolling elements to support the loads on the shaft or journal. Roller bearings differ from other types of bearings, such as ball bearings, in several ways. One key difference is that roller bearings can handle both radial and thrust loads, while ball bearings can only handle radial loads.

Additionally, roller bearings typically have a higher load capacity than ball bearings. Another key difference is that roller bearing have a higher friction coefficient than ball bearings, meaning they are not as efficient in terms of energy usage. Finally, roller bearings tend to be more expensive than ball bearings.

How Roller Bearing is different from cylindrical roller bearing?

Roller bearings are one type of bearing that uses rolling elements to support loads. These rolling elements, called rollers, can be cylindrical, needle-shaped, or spherical. Roller bearings can support heavy radial loads and moderate thrust loads in either direction.

Cylindrical roller bearings are a subset of roller bearings that have cylindrical-shaped rollers. These rollers are typically wider than they are long and they have a barrel-shaped profile. Cylindrical roller bearings can support heavy radial loads and high thrust loads in one direction.

Based on usage

Roller bearings are classified as either radial or thrust bearings based on their intended usage. Radial roller bearings handle mainly radial loads, while thrust roller bearings handle mainly axial loads. However, both types of roller bearings can accommodate some amount of mixed loading. Cylindrical roller bearings, on the other hand, are only designed to accommodate radial loads.

Based on the surface area

Roller bearings are classified as either spherical or cylindrical. The main difference between these two types of roller bearings is the surface area that comes into contact with the inner and outer rings. Spherical roller bearings have a greater surface area than cylindrical roller bearings. This gives them the ability to handle higher loads. However, this also makes them more expensive to manufacture.

Based on load capacity

Roller bearings are also classified as either single-row or double-row. This designation is based on the number of rows of rollers that come into contact with the inner and outer rings. Single-row roller bearings can handle lower loads than double-row roller bearings. Double-row roller bearings are more expensive to manufacture than single-row roller bearings.

Based on Reuse and Replacement

When it comes to roller bearings, there are two main types: roller bearings and cylindrical roller bearings. Both types of bearings have their own unique benefits and drawbacks that make them suitable for different applications.

Key Difference Between Roller Bearing and Cylindrical Roller Bearing

Here’s a quick rundown of the key difference between roller bearing and cylindrical roller bearing that will help you understand the role of two different bearings without any doubt:

Roller Bearings:

Roller bearings are typically cheaper than cylindrical roller bearings.

Roller bearings can be reused more easily than cylindrical roller bearings.

Roller bearings generally have a shorter lifespan than cylindrical roller bearings.

Roller bearings have greater stability and rigidity.

Cylindrical Roller Bearings:

Cylindrical roller bearings can handle higher loads than roller bearings.

Cylindrical roller bearings are less likely to suffer from misalignment issues than roller bearings.

Cylindrical roller bearings typically have a longer lifespan than roller bearings.

Conclusion

In conclusion, roller bearings and cylindrical roller bearings are two types of bearings that serve different purposes. Roller bearings are designed for use in applications where there is a need for high load capacity and low speed, whereas cylindrical roller bearings are designed for use in high-speed applications.

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