Roller Bearings

Used across the automotive, agricultural and industrial sector, roller bearings are vital for supporting radial and axial load as well as reducing friction in large machinery. Here at Cromwell, we have a wide range of roller bearings including various types, from leading brands such as Koyo, FAG and NTN SNR.

What are roller bearings?

Similar to ball bearings, roller bearings are a small component that use a cylindrical rolling element to sustain a degree of separation between the moving parts of the bearing. Designed for aiding movement in machinery - usually in shafts to support radial or axial load - they offer a greater degree of strength than standards ball bearings. There are various roller bearing types that are capable of handling differing loads, including needle, tapered, spherical, cylindrical and yoke track.

When are roller bearings used?

Roller bearings are generally used in low-speed operations (when compared to ball bearings, which are most commonly used in higher speed applications) such as in shafts in various machinery. They are commonly found in the automotive industry in gearboxes, motors and transmission systems, in the agricultural industry and plumbing applications.

Considerations when choosing a roller bearing

Type - There are many types of roller bearing, which have differing capacities when it comes to bearing a load. The most common types are:

Needle - So named due to its thin design, needle roller bearings are primarily suited for high-speed, heavy-load applications. These are designed to handle higher radial loads despite their thin design, working in a similar way to cylindrical roller bearings.

Tapered - These roller bearings are designed to accommodate for both axial and radial forces due to their angular design, and are therefore commonly used in automotive and general industrial sectors.

Spherical - Most similar to ball bearings in their application, spherical roller bearings possess barrel shaped rollers that are designed for use at low to medium operational speeds. These are also effective at dealing with misalignment and shaft deflection as well as axial loading in either direction.

Cylindrical - These type of roller bearings are suited for bearing heavy radial loads and withstanding high speed operations. Their distinguishing feature is their rollers that are longer tan their diameter, which allows them to operate more effectively under a high load than ball bearings.

Yoke Track - Able to support both radial and axial loads, yoke track roller bearings have a thick walled outer ring and are commonly used in conveying systems and cam gears.

Outside Diameter - As it sounds, this is the diameter as measured from the outer ring of the roller bearing to the opposite side. This is almost always metric in size and is best measured using a vernier calliper.

Inside Diameter - Measured from one side to the other of the inner hole, this denotes the diameter of the inner. The same as the outside diameter, this is usually metric and is best measured using a vernier calliper for maximum accuracy.

Width - The last measurement needed when determining the correct bearing size, this is the measurement of the roller bearing as seen from the side, the thickness of the roller bearing. As above, this is usually measured in metric sizes and is most accurately measured using a vernier calliper.

Roller bearing jargon buster

We want to make it easy for you, so here are some key terms that will help you understand the range and applications of the various types of roller bearings a little better.

What is a radial direction?
Radial direction simply refers to a downwards force. The radial load is the force which is perpendicular to the motion.

What is an axial direction?
Conversely, an axial direction is a sideways or thrust force. This occurs parallel to the motion.


What are roller bearings good for?

Roller bearings have many useful applications, but the most common is in main shaft and auxiliary drive shafts. They are useful in any machine part that is subject to radial or axial force.