The RU52 cross roller bearing is a compact mounting-holed precision bearing with a 25 mm bore, 80 mm outside diameter and 12 mm width. Its integrated inner and outer rings allow direct installation without a separate bearing housing or clamping flange in many applications.
RU52 has an 8.61 kN basic dynamic load rating, a 10.6 kN basic static load rating and an approximate mass of 0.40 kg. It is suitable for compact robot wrists, small indexing tables, optical inspection devices, semiconductor automation and precision measuring systems.
LYDL supplies open RU52 and sealed RU52UU versions with selectable clearance, preload and P5, P4 or P2 accuracy options. Dimensional reports, rotational inspection and protective export packaging are available for OEM and replacement orders.
RU52 Cross Roller Bearing | Reliable 25×80×12 mm
The RU52 cross roller bearing is a compact crossed cylindrical roller bearing with integrated inner and outer rings. Its rollers are arranged alternately at right angles.
This internal arrangement allows one bearing position to support radial load, axial load and overturning moment.
RU52 measures 25 × 80 × 12 mm and weighs approximately 0.40 kg. It is designed for small rotary systems where axial space, assembly weight and positioning accuracy must be controlled.
Mounting holes are machined into both rings. In many applications, the bearing can be installed directly without a separate housing or retaining flange.
View the complete RU cross roller bearing series or explore our cross roller bearing category for alternative sizes and structures.
RU52 Cross Roller Bearing Specifications
Parameter
RU52 specification
Bore diameter, d
25 mm
Outside diameter, D
80 mm
Bearing width, B
12 mm
Roller pitch circle diameter, dp
52.5 mm
Basic dynamic load rating, C
8.61 kN
Basic static load rating, C₀
10.6 kN
Approximate mass
0.40 kg
Reference inner shoulder diameter
46.5 mm maximum
Reference outer shoulder diameter
58.5 mm minimum
Minimum chamfer radius, r
0.6 mm
Reference lubrication-hole diameter
3.1 mm
Inner-ring bolt-circle diameter
35 mm
Inner-ring mounting holes
6 × M3 threaded through holes
Outer-ring bolt-circle diameter
67 mm
Outer-ring mounting holes
6 × Ø3.4 through holes
Outer-ring counterbores
Ø6.5 mm, 3.3 mm deep
Available structure
Open or sealed
Available accuracy
P5, P4 or P2
Typical clearance options
CC0, C0 or application-specific
Optional grease-fitting reference
NP3.2×3.5, subject to drawing
The listed dimensions and ratings are catalog reference values. Final production requirements must follow the LYDL-approved drawing and purchase specification.LYDL RU52 cross roller bearing with M3 inner-ring holes and counterbored outer-ring holes.
Key Advantages of the RU52 Cross Roller Bearing
Compact 12 mm Width
RU52 provides a 25 mm bore and 80 mm outside diameter while maintaining a width of only 12 mm.
It fits between RU42 and RU66 when RU42 is too small but the additional width and diameter of RU66 are unnecessary.
Direct Mounting Structure
The RU52 cross roller bearing has mounting holes in both rings. This can reduce the number of surrounding components and shorten the assembly tolerance chain.
Direct mounting does not eliminate the need for rigid support. Uneven or flexible mounting plates can distort the bearing rings.
Combined-Load Support
The crossed roller arrangement supports radial, axial and moment loads in one compact bearing position.
For an offset payload, selection should consider the payload, moment arm, acceleration and emergency-stop load. Vertical load alone is not sufficient.
Low Assembly Mass
RU52 weighs approximately 0.40 kg. Its compact size helps control the mass of small robot joints, instrument axes and positioning systems.
Total system inertia also depends on the motor, flange, payload and their distances from the rotational center.
RU52 Mounting-Hole Arrangement
The standard RU52 configuration uses:
Six M3 threaded through holes on a 35 mm inner-ring PCD
Six Ø3.4 mm through holes on a 67 mm outer-ring PCD
Ø6.5 mm outer-ring counterbores with a depth of 3.3 mm
The M3 threaded inner ring allows bolts to engage directly with the bearing. The counterbored outer-ring holes provide recessed bolt-head installation from the designated side.
Bolt direction and installation access should be checked on the assembly drawing before an order is confirmed.
Open structure with the standard mounting-hole pattern
RU52UU
Seals installed on both sides
RU52U
One-side seal; orientation must be confirmed
RU52UT
One-side seal on the opposite face
RU52CC0
Controlled negative-clearance or preload specification
RU52C0
Normal reference clearance specification
RU52P5
Precision option for general positioning equipment
RU52P4
Higher accuracy for inspection and indexing axes
RU52P2
Ultra-precision option subject to inspection agreement
RU52-N
Optional grease fitting; interface must be confirmed
Clearance, preload and accuracy codes are not identical across all manufacturers.
When replacing another brand, record the required numerical clearance, runout and torque instead of relying only on the suffix.
Are RU52G and RU52X Standard Models?
RU52G and RU52X should not be listed as regular standard variants.
G and X mounting-hole codes are generally used for larger RU124–RU445 bearings. They describe alternative counterbore directions or inner-ring threaded-hole arrangements.
RU52 already has M3 threaded holes in the inner ring and counterbored holes in the outer ring.
If a customer requires reversed counterbores or different mounting threads, the bearing should be treated as a customized RU52 rather than automatically designated RU52G or RU52X.
RU52 Cross Roller Bearing Applications
The RU52 cross roller bearing can be used in:
Compact industrial robot wrists
Small collaborative robot joints
Precision rotary and indexing tables
Optical inspection equipment
Camera and sensor positioning axes
Semiconductor handling systems
Laboratory automation equipment
Precision measuring instruments
Small antenna positioners
Hollow-shaft motor assemblies
Automated dispensing equipment
The 25 mm bore may accommodate a small shaft, electrical cable or pneumatic line.
The usable opening can be smaller after installing shoulders, fasteners and cable connectors. Cable bend radius must also be considered.
For cantilevered robot tools, calculate the overturning moment from the payload and its distance from the bearing center.
The 10.6 kN static rating should not be interpreted directly as the maximum allowable equipment payload.Typical RU series applications include compact robots, rotary actuators, inspection systems and laboratory automation
RU52 is not simply a higher-capacity RU42. Its main advantage is the intermediate 25 mm bore and 80 mm outside diameter.
RU66 should be considered when load capacity and moment rigidity are more important than minimum size.
See our cross roller bearing selection guide for additional selection factors.
Need an RU52 Drawing or Quick Quotation?
If the model has been selected, send the RU52 or RU52UU designation, accuracy, clearance, quantity and delivery destination.
If selection is not finalized, provide the radial load, axial load, moment arm, speed, duty cycle and mounting envelope. Request an RU52 technical review and quotation
RU52 and IKO CRBF2512AT Interchange Reference
RU52 is commonly compared with IKO CRBF2512AT. The corresponding two-side sealed reference is CRBF2512ATUU.
The commonly published reference specifications include:
25 × 80 × 12 mm boundary dimensions
35 mm inner-ring PCD
Six M3 inner-ring threaded holes
67 mm outer-ring PCD
Six counterbored outer-ring holes
8.61 kN dynamic load rating
10.6 kN static load rating
Approximately 0.40 kg mass
These similarities support dimensional comparison. They do not automatically guarantee complete interchangeability.
Before approving a replacement, compare:
Dimensional tolerances
Mounting-hole positions
Counterbore depth and direction
Seal structure
Clearance or preload
Radial and axial runout
Starting and running torque
Grease type and fill quantity
Lubrication-port position
IKO uses its own AT, ATUU, T1, C1 and C2 codes. These codes should not be automatically converted into LYDL or other manufacturers’ suffixes.
The cited current THK RU table lists RU42 followed by RU66. It does not identify RU52 as a standard THK model.
If a customer requests a THK replacement, obtain the original bearing label or drawing before confirming interchangeability.
IKO and THK names belong to their respective owners. They are used solely for identification and technical comparison.
LYDL is an independent manufacturer and does not claim affiliation with or endorsement by these brands.
Engineering Standards and References
The following references support consistent bearing terminology, calculations and inspection requirements:
IKO General Product Catalog — CRBF2512AT and CRBF2512ATUU dimensions, mounting pattern and reference ratings: IKO General Product Catalog
THK Model RU Technical Data — integrated RU structure, mounting-hole conventions, seal codes and the applicable G/X model range: THK Cross-Roller Ring Technical Data
THK RU Product Overview — general RU construction and application characteristics: THK Standard Models RU
ISO 281:2007 — rolling-bearing dynamic load ratings and rating life: ISO 281:2007
ISO 76:2006 — rolling-bearing static load ratings: ISO 76:2006
ISO 492:2023 — radial bearing geometrical specifications and tolerance values: ISO 492:2023
ISO 15:2017 — radial bearing boundary-dimension principles: ISO 15:2017
ISO 15243:2017 — classification of rolling-bearing damage and failure modes: ISO 15243:2017
These sources provide general terminology and calculation frameworks.
The approved LYDL drawing, inspection agreement and purchase order remain the controlling documents for the supplied bearing.
RU52 Installation Recommendations
Inspect the Mounting Surfaces
Clean both mating surfaces before installation.
Remove burrs, particles and raised material around the threaded holes. Surface errors can deform the 12 mm-wide bearing and create uneven torque or runout.
Both rings should be supported by continuous, rigid mounting surfaces.
Protect the M3 Threads
The six inner-ring holes use M3 threads. Fastener selection and tightening control are therefore important.
Excessive torque may damage the threads or distort the ring locally.
Determine the bolt grade, engagement length and tightening torque from the actual joint design. Do not apply a generic torque value without considering the mating material and thread condition.
Tighten in Several Stages
Insert all fasteners before final tightening.
Use a diagonal sequence and increase the torque gradually. Check that the bearing remains seated and rotates smoothly during installation.
Do not use the mounting bolts to pull misaligned components together.
Check the Filler-Plug Position
If the bearing includes a roller-filling plug, avoid positioning it directly in the highest repetitive load zone whenever possible.
Record the final orientation when production traceability is required.
Perform a Low-Speed Run-In
Rotate the assembly slowly after installation.
Check for abnormal torque, noise, vibration or temperature rise. Increase speed and load gradually.
For short-stroke oscillation, verify that grease reaches the active roller contact area.
RU52 Inspection and Export Packaging
LYDL inspection for an RU52 cross roller bearing may include:
Bore, outside diameter and width measurement
Inner- and outer-ring PCD inspection
M3 thread verification
Counterbore size and depth inspection
Clearance or preload confirmation
Radial and axial runout inspection
Starting and running-torque measurement
Seal and lubrication-port inspection
Appearance and marking verification
Inspection report or product photographs
After inspection, the bearing is cleaned and protected against corrosion.
Each bearing is packaged to prevent moisture, movement and impact during international transportation. Individual separation prevents metal-to-metal contact in batch shipments.dimensional inspection, rotation testing and protective export packaging at LYDL.
Why Source RU52 from LYDL?
Open RU52 and sealed RU52UU configurations
P5, P4 and P2 accuracy options
Application-specific clearance or preload
Mounting-hole and M3 thread inspection
Rotational runout and torque reports
Grease and sealing customization
OEM marking and batch traceability
Small replacement and production orders
Protective export packaging
Application-based technical support
RU52 Cross Roller Bearing FAQ
Why choose RU52 instead of RU42?
RU52 increases the bore from 20 mm to 25 mm while retaining a 12 mm width.
It is useful when RU42 does not provide enough shaft or cable-routing space but RU66 is too large.
Why are RU52G and RU52X not standard variants?
RU52 already has threaded inner-ring holes and counterbored outer-ring holes.
The G and X mounting codes are normally used for larger RU bearings with alternative mounting-hole arrangements.
Can RU52 replace IKO CRBF2512AT?
Their nominal dimensions, mounting pattern and reference load ratings correspond closely.
However, clearance, accuracy, torque, seals, grease and dimensional tolerances must be checked before replacement.
Can cables pass through the 25 mm bore?
Small cables, tubes or a shaft may pass through the bore.
The usable space depends on shoulders, fasteners, connectors and cable bend radius.
Why is M3 bolt control important?
Small M3 threads provide less tolerance for excessive tightening.
Uneven bolt force can also distort the narrow rings and affect rotational torque.
Is RU52 suitable for a cantilevered robot wrist?
RU52 can be used in compact robot wrists.
Selection must include payload distance, overturning moment, acceleration, shock load and required rigidity.
When should RU66 be selected?
Consider RU66 when a 35 mm bore is required or RU52 does not provide sufficient calculated capacity.
RU66 requires more installation space but offers substantially higher load ratings.
