Bearing + Bushing Selection Guide
Bearing and bushing selection begins with motion, load, and the interfaces between the moving component, shaft, and housing. Speed, radial and axial loading, shaft fit, housing fit, lubrication, alignment, material, sealing, temperature, contamination, and maintenance all influence which motion support component is appropriate.
Define the Motion Support Requirement
Start by defining how the supported member moves and how forces enter the bearing or bushing. Dimensional fit and operating environment can then be evaluated around that basic motion requirement.
Motion Type
Determine whether the application uses continuous rotation, intermittent rotation, linear travel, oscillation, indexing, or another motion pattern.
Load Direction
Identify radial, axial, combined, overturning, shock, static, dynamic, and cyclic loads acting on the support.
Speed
Record continuous, peak, startup, reversing, and intermittent speeds because friction and heat generation can change substantially with operating speed.
Shaft + Housing Fit
Define shaft diameter, housing diameter, width, shoulder geometry, retention, mounting dimensions, and required clearance or interference.
Lubrication
Determine whether grease, oil, dry running, self-lubricating materials, external lubrication, or sealed-for-life construction is appropriate.
Environment
Evaluate temperature, moisture, dust, washdown, process fluids, corrosion, vibration, contamination, cleanliness, and maintenance access.
Match bearing geometry to the load path.
Bearing type should reflect not only the magnitude of the load but also its direction, duration, movement, and relationship to speed.
A component suitable for radial loading may not provide the same capability under significant axial or combined loading.
Check the Shaft, Housing, and Alignment
Bearing dimensions are part of a complete mounting interface. Shaft condition, housing geometry, retention, alignment, thermal expansion, and assembly method can all affect operating clearance and service life.
Shaft Interface
Verify diameter, surface condition, hardness where relevant, shoulder geometry, roundness, finish, and retention method.
Housing Interface
Confirm housing bore, width, shoulders, retaining features, alignment, structural stiffness, and mounting geometry.
Operating Clearance
Installation fit, temperature, load, material expansion, and preload can change the internal or running clearance available during operation.
Alignment
Shaft position, housing position, support spacing, deflection, and mounting accuracy should be compatible with the selected bearing or bushing type.
Select Construction and Material
Material affects load capability, friction, corrosion, lubrication requirements, electrical behavior, temperature performance, wear, weight, and contamination tolerance.
Four-Step Bearing + Bushing Selection Process
Use the load path, motion, and mounting interfaces as the main reference points when comparing candidates.
Define Motion + Load
Record motion type, speed, load direction, load magnitude, shock, cycling, duty, and expected shaft or structure movement.
Define the Interfaces
Specify shaft diameter, housing dimensions, width, shoulders, retaining features, mounting arrangement, clearances, and available space.
Select Type + Material
Choose rolling or sliding support, internal geometry, material, seals, lubrication method, and construction suited to load, speed, and environment.
Verify Installation
Check shaft and housing condition, alignment, assembly method, lubrication access, temperature, contamination, retention, and future replacement.
Installation + Service Checks
Bearing performance depends heavily on the surfaces and structure around it. Correct selection should therefore include the conditions under which the component will be mounted and maintained.
- Confirm shaft and housing dimensions before assembly.
- Inspect shaft and housing surfaces for damage, wear, contamination, or distortion.
- Verify shoulders, retaining rings, spacers, sleeves, and locking hardware.
- Confirm the selected fit and installation method are appropriate.
- Avoid transmitting damaging assembly force through inappropriate bearing elements.
- Verify alignment before placing the system into service.
- Use the intended lubricant or dry-running configuration.
- Confirm relubrication access if periodic lubrication is required.
- Protect the bearing from contamination during storage and installation.
- Monitor temperature, noise, vibration, wear, or movement where appropriate.
- Inspect seals and protective features in contaminated environments.
- Document replacement size, fit, material, and lubrication requirements.
Common Bearing Selection Mistakes
Dimensional similarity does not guarantee equal load, speed, internal geometry, material, lubrication, or environmental performance.
Matching Bore Only
The same shaft diameter does not guarantee compatible outside diameter, width, housing fit, internal clearance, or load capability.
Ignoring Load Direction
A bearing selected for radial loading may not provide the required performance under significant axial or combined loads.
Treating Speed as Secondary
Speed influences friction, heat, lubrication, cage behavior, material choice, and overall operating suitability.
Ignoring Shaft + Housing Fit
Incorrect mounting fit can change internal clearance, allow unwanted movement, or create excessive stress.
Overlooking Lubrication
A suitable bearing type can still fail prematurely if lubrication type, amount, contamination control, or service interval is inappropriate.
Ignoring Misalignment
Shaft deflection, mounting error, and structural distortion can place unintended loads on components that are not designed to accommodate them.
Related Bearing + Motion References
Use these references for additional information on bearings, linear motion, drive components, and compatibility.
Background information on bearings, bushings, motion, loads, materials, and selection factors.
Related technologies used to create and guide mechanical movement.
Technical references for comparing replacement bearings, bushings, and related motion components.