Supports Movement
Bearings help shafts, rollers, wheels or machine parts move more smoothly while staying supported in the correct position.
BMG World Bearing Support
What is a Bearing?
A bearing is a machine component that helps support movement between parts. In industrial equipment, bearings are commonly used to support shafts, wheels, rollers and rotating components while helping reduce friction and carry load.
Reduces Friction
Bearings are used to reduce friction between moving parts, helping equipment run more smoothly when correctly selected and installed.
Carries Load
Bearings help transfer load between machine components, but the correct type depends on load direction, speed, fit and operating conditions.
Bearing Basics Guide
Understanding bearings before choosing a replacement
Bearings are used across industrial machinery to help moving parts rotate, oscillate or slide with less friction. For maintenance and procurement teams, the important question is not only what a bearing is, but which bearing type, size and specification matches the machine.
What is a bearing?
A bearing is a component that supports movement between machine parts. In many industrial applications, a bearing supports a rotating shaft, wheel, roller or mounted component while helping reduce friction and transfer load. Bearings are used in equipment such as motors, pumps, conveyors, gearboxes, fans, agricultural machinery, mining equipment and workshop machinery.
Supports movement The bearing helps a rotating or moving part stay supported in the machine while allowing controlled movement.
Reduces friction The bearing helps reduce friction between moving surfaces when it is correctly selected, installed and lubricated.
Carries load The bearing helps carry or transfer load between machine components, depending on load direction, bearing type and application conditions.
1. The moving part needs support
A shaft, wheel, pulley, roller or gear needs to stay aligned while it moves. The bearing helps support that part in the correct machine position.
2. Friction needs to be controlled
Without the right bearing, moving parts can create excessive friction, heat or wear. The bearing helps movement take place more smoothly.
3. Load needs to be carried
Different bearings are selected for different radial, axial or combined load conditions. The correct selection depends on the machine design.
Do not choose by size alone
Two bearings may look similar or have similar dimensions but still differ by internal design, seal type, shield type, clearance, cage, load direction, speed suitability, lubrication method or suffix. Always confirm the full bearing reference and live product details before ordering.
What are the main parts of a bearing?
Many rolling bearings include an inner ring, outer ring, rolling elements and a cage. The rolling elements may be balls or rollers, depending on the bearing type. Some bearings may also include seals, shields, collars, housings or other features depending on the product and application.
Inner ring
The inner ring is commonly fitted around the shaft or rotating component, depending on the bearing arrangement.
Outer ring
The outer ring is commonly supported by the housing or surrounding machine component, depending on the design.
Rolling elements
Balls or rollers sit between the rings in many rolling bearings and help the bearing carry load with rolling motion.
Cage
A cage can help space and guide the rolling elements, depending on the bearing design and product type.
Seals or shields
Some bearings include seals or shields to help protect the internal bearing area or retain lubricant, depending on the variant.
Housing or unit
Some bearings are supplied as bearing units or housed arrangements for easier mounting and shaft support in industrial equipment.
Common types of bearings
Bearings are grouped by design and application. The right type depends on the load direction, speed, shaft size, housing, lubrication, sealing, space available and operating environment.
Ball bearings
Ball bearings use balls as rolling elements. They are commonly used in many rotating applications, but the exact selection depends on the bearing design and product listing.
Roller bearings
Roller bearings use rollers as rolling elements. They are often considered where load handling, rigidity or specific machine conditions require a roller bearing design.
Deep groove ball bearings
Deep groove ball bearings are widely used in general rotating equipment. Confirm seals, shields, clearance, dimensions and suffix before ordering.
Tapered roller bearings
Tapered roller bearings are used in applications where their design matches the load and mounting requirements. Confirm arrangement and specification before replacing.
Spherical roller bearings
Spherical roller bearings may be used where the machine design requires that bearing type. Check load, alignment, fit, lubrication and manufacturer guidance before selection.
Needle bearings
Needle bearings use smaller-diameter rollers and may be selected where the machine design and available space require that type.
Thrust bearings
Thrust bearings are designed for axial load arrangements. Confirm load direction and machine design before selecting or replacing one.
Bearing units
Bearing units combine a bearing and housing arrangement for shaft support. Confirm housing type, mounting style and insert bearing details before ordering.
What is the difference between ball bearings and roller bearings?
Ball bearings use balls as rolling elements, while roller bearings use rollers. This difference affects how the bearing carries load, how it behaves at speed, and where it is commonly used. Neither type is automatically better for every machine. Selection depends on load direction, speed, shaft and housing design, lubrication, sealing and operating conditions.
Where are bearings used in industrial equipment?
Bearings are found in many rotating and moving machine positions. In industrial environments, they are commonly associated with motors, pumps, conveyors, gearboxes, fans, rollers, agricultural machinery, mining equipment, construction equipment, workshop tools and general MRO applications.
Rotating shafts Used to support shaft movement in motors, pumps, gearboxes, fans and other rotating equipment.
Conveyors and rollers Used in rollers, pulleys and conveyor-related equipment where supported rotation is required.
Heavy-duty machinery Used in mining, manufacturing, agriculture and construction machinery where bearing selection must match the operating conditions.
Maintenance spares Kept as replacement parts by stores and MRO teams, but should be identified by full bearing number and suffix before use.
What to check before choosing a replacement bearing
A replacement bearing should be selected from the complete machine requirement, not from one detail only. Use the removed bearing, machine position and operating conditions as the starting point.
Full bearing number Record the complete bearing number, including brand, suffixes, spaces, hyphens, seal or shield codes and any clearance markings.
Bearing type Confirm whether the part is a ball bearing, roller bearing, thrust bearing, bearing unit or another bearing type.
Dimensions Check bore, outside diameter and width where needed, especially if the old bearing marking is incomplete or unreadable.
Load and speed Confirm whether the position carries radial load, axial load or combined load, and check the operating speed against the product details.
Seals and lubrication Check whether the bearing is open, sealed, shielded, grease-lubricated, oil-lubricated or part of a machine lubrication system.
Machine environment Consider dust, moisture, temperature, vibration, shock loading, washdown, maintenance access and whether the position has failed before.
How do I know which bearing I need?
Start with the bearing already fitted to the machine. Record the full bearing number, suffix, brand and visible markings. If the number is unreadable, measure the bearing and capture photos of the bearing, housing, shaft and machine position. Then confirm the live product details before ordering.
Frequently asked questions
What is a bearing?
A bearing is a machine component that supports movement between parts. It helps rotating or moving components run more smoothly while carrying load and reducing friction when correctly selected and installed.
What does a bearing do?
A bearing helps support a shaft, wheel, roller or moving part, reduce friction, guide movement and transfer load between machine components. The exact function depends on the bearing type and application.
How does a bearing work?
Many bearings work by placing rolling elements, such as balls or rollers, between rings so movement can take place with less friction. Other bearing types may use sliding surfaces or different designs.
Where are bearings used in industrial equipment?
Bearings are used in motors, pumps, conveyors, gearboxes, rollers, fans, agricultural equipment, mining machinery, construction equipment, workshop machinery and many other rotating or moving machine positions.
What are the main parts of a bearing?
Many rolling bearings include an inner ring, outer ring, rolling elements and a cage. Some also include seals, shields, collars, housings or other features depending on the bearing type.
What are common types of bearings?
Common industrial bearing types include ball bearings, roller bearings, deep groove ball bearings, tapered roller bearings, spherical roller bearings, needle bearings, thrust bearings and bearing units.
What is the difference between ball bearings and roller bearings?
Ball bearings use balls as rolling elements, while roller bearings use rollers. This difference affects load handling, speed behaviour, space requirements and application suitability. Confirm the machine requirement before choosing.
How do I know which bearing I need?
Check the full bearing number, suffix, brand, dimensions, seal or shield type, clearance marking, load direction, speed, shaft, housing, lubrication method and operating environment before ordering.
What should I check before replacing a bearing?
Check the removed bearing, shaft, housing, lubricant condition, seals, mounting method, machine position and operating conditions. If the old bearing failed early, investigate the cause before fitting another replacement.
Can I choose a bearing by size alone?
No. Size alone is not enough. Bearings with similar dimensions can differ by type, clearance, seal, shield, cage, load direction, speed suitability and suffix. Confirm the full product details before ordering.
Where can I find industrial bearings in South Africa?
BMG supplies industrial bearings for South African maintenance, manufacturing, mining, agriculture, construction and MRO applications. View the BMG Bearings range and confirm the live product details before ordering.
Need to identify or replace a bearing?
Start with the bearing number, suffix and machine position. Then check the BMG Bearings range for industrial bearing options and confirm the live product details before ordering.