Views: 1 Author: Rose Zhang Publish Time: 2026-11-10 Origin: Nexans Bearing
To choose a cylindrical roller bearing, first determine whether the bearing position must carry radial load only, locate the shaft axially, or allow axial movement. Then confirm the exact bearing design, load, speed, internal clearance, shaft and housing fits, and lubrication method. Two cylindrical roller bearings with similar dimensions can perform different functions in the same machine.
Cylindrical roller bearings are widely considered for industrial gearboxes, electric machinery, pumps, and other equipment with demanding radial loads. Their design can provide high radial load capacity, but their ability to carry axial load depends on the specific bearing configuration. That distinction is critical when sourcing replacements or approving a new design.
This guide explains the main selection questions for OEM buyers, maintenance teams, and bearing distributors. To review product options, visit the Nexans Bearing product catalog.
A cylindrical roller bearing uses cylindrical rolling elements between its inner and outer rings. Compared with a similarly sized deep groove ball bearing, a suitable cylindrical roller bearing design may offer greater radial load capacity. Actual suitability still depends on the specific model and operating conditions.
Cylindrical roller bearings are available in several configurations. The position of the flanges on the inner and outer rings affects whether the bearing permits axial movement between the rings or can support axial load in one or both directions within design limits.
Buyer takeaway: Do not order a cylindrical roller bearing by bore, outside diameter, and width alone. Confirm its complete designation and role in the shaft arrangement.
Selection factor | What to confirm |
Bearing position | Gearbox, motor, pump, or other machine location |
Shaft function | Locating or non-locating bearing position |
Bearing design | Exact configuration specified by the equipment design |
Loads | Radial load, any axial load, shock, and duty cycle |
Dimensions | Bore, outside diameter, width, and mounting details |
Internal clearance | Required clearance before and after mounting |
Speed | Normal and maximum operating speed |
Fits | Shaft and housing seat dimensions and conditions |
Lubrication | Grease or oil supply and operating temperature |
Environment | Contamination, vibration, moisture, and maintenance access |
If you are replacing an existing bearing, use the equipment manufacturer’s specification as the primary reference.
Many shafts are supported by more than one bearing. In a common arrangement, one bearing position locates the shaft axially, while another position allows for axial movement caused by thermal expansion. The specific design may use a different approach, so the equipment drawing should always be checked.
Some cylindrical roller bearing configurations allow axial displacement between their inner and outer rings. Others can support axial load in one direction or provide axial location in both directions within their design limits.
Before sourcing a bearing, ask:
Is this the locating or non-locating position?
Must the shaft move axially as it heats up?
Which bearing or component carries the axial load?
Has the equipment manufacturer specified an exact bearing configuration?
Installing an axially locating design where movement is required—or a non-locating design where the shaft must be located—can create serious operating problems even if the bearing fits the shaft and housing.
Designations such as NU, N, NJ, and NUP are commonly used to identify cylindrical roller bearing configurations. Their flange arrangements affect how the bearing functions in an assembly.
Common design | General functional characteristic |
NU | Typically permits axial displacement between the inner and outer rings |
N | Typically permits axial displacement between the inner and outer rings |
NJ | Can support axial load in one direction within its design limits |
NUP | Can provide axial location in both directions within its design limits |
This table is an introduction, not a substitution chart. Specific design details, supplementary components, and suffix meanings should be verified against the proposed manufacturer’s product documentation.
For example, replacing an NU bearing with an NJ bearing of matching basic dimensions changes the bearing position’s axial behavior. Whether that change is acceptable can only be determined from the machine’s complete shaft arrangement.
Cylindrical roller bearings are often selected for their radial load capacity. However, the application may also impose axial forces from gears, couplings, or other machine components.
Collect as much of the following information as possible:
normal radial operating load;
maximum or shock load;
axial load magnitude and direction;
continuous or intermittent duty;
starts and stops; and
the role of other bearings on the shaft.
An NJ or NUP design may provide axial guidance, but its permissible axial load is not unlimited. The bearing’s published guidance and the application’s lubrication and speed conditions must be reviewed.
If axial load is substantial, do not assume that changing from one cylindrical roller bearing configuration to another will solve the problem. The complete bearing arrangement may need engineering review.
Cylindrical roller bearings are used across a range of operating speeds. Their suitability at a given speed depends on bearing design, load, clearance, lubrication, and mounting conditions.
For an accurate product review, provide:
normal and maximum shaft speed;
expected operating temperature;
load and duty cycle;
grease or oil lubrication method; and
any history of overheating.
A bearing that runs hot may have a problem involving clearance, fit, lubrication, load, or assembly. Do not assume the solution is simply a bearing with a higher published speed value.
Internal clearance can change when a bearing is mounted on a shaft and operates at temperature. An interference fit can reduce the clearance available after installation. Temperature differences between bearing rings can change it further.
Buyers should therefore confirm whether the application specifies Normal clearance or another clearance class rather than choosing one by habit.
Too little working clearance may contribute to excessive heat and early damage. Too much may affect running behavior, depending on the application.
When requesting selection support, share the shaft and housing fits, operating temperature, speed, and complete bearing designation. For a replacement order, retain the approved clearance specification unless an engineering review supports a change.
Bearing fits help keep the rings correctly seated under load. The appropriate fit depends on which ring rotates relative to the load, as well as load magnitude, vibration, temperature, and the machine’s mounting requirements.
Inspect the shaft and housing if previous bearings have shown:
fretting or movement at the bearing seat;
uneven contact marks;
difficult mounting;
repeated overheating; or
unexpectedly short service life.
A new bearing cannot compensate for an incorrectly sized shaft or a damaged housing seat. Conversely, specifying an excessively tight fit may reduce working clearance. Fit and clearance should be reviewed together.
Industrial gearboxes commonly use an oil system, while other equipment may use grease lubrication. The correct method depends on the machine design and bearing position.
Confirm:
whether lubricant can reach the bearing contacts;
lubricant type and operating temperature;
normal and maximum speed;
maintenance or relubrication access; and
protection against contamination.
For a gearbox replacement, changing the bearing configuration may also change the way lubricant reaches the rolling elements. Follow the equipment specification and examine the complete lubrication path before approving a substitution.
Identify the bearing’s location on the shaft and determine which position provides axial location. Confirm gear-generated loads, operating speed, oil supply, and thermal expansion requirements. An apparently minor change in bearing design can affect the gearbox’s shaft arrangement.
Some motor designs use a cylindrical roller bearing where higher radial load capacity is required. Confirm the motor manufacturer’s bearing arrangement, shaft fits, operating speed, and clearance requirements. Do not replace a ball bearing with a roller bearing based only on matching dimensions.
Review radial load, shock, shaft support, contamination, and maintenance access. For repeated failures, inspect the bearing seats and lubrication system rather than changing the bearing specification without a root-cause review.
You can browse the bearing product range at Nexans Bearing while preparing a model-specific inquiry.
Avoid these errors when buying cylindrical roller bearings:
Treating NU, N, NJ, and NUP designs as interchangeable.
Ordering by basic dimensions while ignoring the full designation.
Failing to identify the locating and non-locating bearing positions.
Assuming every cylindrical roller bearing can carry axial load.
Selecting clearance without accounting for mounting fits.
Overlooking shaft or housing seat damage.
Changing a gearbox bearing without checking lubrication and shaft movement.
Assuming a cross-reference is approved without verifying the machine application.
A reliable replacement should match both the bearing specification and its function in the assembly.
For a useful cylindrical roller bearing inquiry, provide:
The full bearing designation, including suffixes.
The equipment type and bearing position.
The OEM reference, drawing, or clear photos, if available.
Bore, outside diameter, width, and relevant shaft and housing dimensions.
Whether the position must locate the shaft or permit axial movement.
Known radial and axial loads.
Operating speed, temperature, and lubrication method.
Required quantity, packaging, and delivery destination.
If the bearing’s axial function is unknown, state that in the inquiry. It is better to identify a missing requirement before ordering than to discover it during installation.
A suitable cylindrical roller bearing design can provide high radial load capacity. Its suitability also depends on speed, clearance, lubrication, and its role in the complete bearing arrangement.
An NU design typically permits axial displacement between its rings. An NJ design can support axial load in one direction within its design limits. They should not be treated as automatic substitutes.
Some designs can; others are primarily intended to accommodate radial load while allowing axial displacement. Check the exact configuration and its published limitations.
Depending on the gearbox design, a non-locating position may allow a shaft to expand or contract axially as temperature changes. The equipment drawing should identify how shaft location is managed.
No. The correct clearance depends on fits, temperature, load, and the required working condition. Increased clearance should not be specified simply because the equipment is heavy-duty.
Not without reviewing the arrangement. A different prefix may indicate a different flange configuration and axial function even when basic dimensions match.
Send the complete designation, required quantity, application, destination, and any drawing or OEM number. Add shaft-arrangement, load, speed, clearance, and packaging details where available.
Visit the Nexans Bearing product catalog. For a specific replacement or OEM project, include your application details so the proposed product can be checked before ordering.
Selecting a cylindrical roller bearing is not just a matter of choosing a size and load rating. The bearing must perform the correct axial function in the machine while meeting its radial load, speed, clearance, mounting, and lubrication requirements.
Begin with the equipment specification and confirm the complete designation—especially whether the design is NU, N, NJ, NUP, or another configuration. Review the Nexans Bearing product catalog, then send your reference number, drawing, application details, and required quantity through the Nexans Bearing website for product and quotation review.
