The RA11008 cross roller bearing is an ultra-thin precision bearing with a 110 mm bore, 126 mm outside diameter and only 8 mm width. It provides a large central opening for cables, optical components, air lines or a hollow drive shaft without requiring a bulky bearing section.
Cylindrical rollers arranged alternately at 90 degrees allow one bearing position to support radial, bidirectional axial and overturning moment loads. The one-piece inner ring is normally used as the rotating ring, while the separable outer ring requires accurate housing support.
LYDL supplies the RA11008 cross roller bearing in open, sealed, C0 and CC0 configurations. Special grease, controlled clearance, higher accuracy and inspection reports can be provided after technical confirmation.
Send your quantity, loads, speed, accuracy, sealing and lubrication requirements for a drawing review and quotation.
RA11008 Cross Roller Bearing Overview
The RA11008 cross roller bearing provides a 110 mm through-bore within a 126 mm outside diameter.
Its width is only 8 mm. This combination helps reduce the axial space and rotating mass of precision rotary mechanisms.
The difference between the bore and outside diameter is 16 mm. The resulting radial section is only 8 mm on each side.
Cylindrical rollers are arranged alternately at 90 degrees between the raceways. One bearing position can support radial load, axial load in both directions and overturning moment.
Spacer retainers separate adjacent rollers. They help reduce roller-to-roller friction and stabilize rotational torque.
RA11008 has a one-piece inner ring and a separable outer ring. The inner ring is normally selected as the rotating ring when running accuracy is important. Caption: RA11008 combines a 110 mm bore with only 8 mm width for compact precision rotary assemblies.
RA11008 Cross Roller Bearing Specifications
The principal RA11008 cross roller bearing dimensions and catalogue ratings are listed below.
Parameter
RA11008 specification
Bore diameter, d
110 mm
Outside diameter, D
126 mm
Width, B
8 mm
Radial section, (D − d) ÷ 2
8 mm
Roller pitch circle, dp
117 mm
Lubrication-hole reference, a × b
2 × 0.8 mm
Minimum corner radius, r min
0.5 mm
Maximum shaft shoulder, ds
113.5 mm
Minimum housing shoulder, Dh
120.5 mm
Basic dynamic radial load rating, C
7.45 kN
Basic static radial load rating, C0
15 kN
Approximate mass
0.15 kg
Ring structure
One-piece inner ring and separable outer ring
Standard lubrication
Grease lubrication
Standard-grease temperature range
−15°C to +80°C
The listed ratings are basic radial catalogue values. They are not direct allowable limits for combined radial, axial and moment loading.
Bearing life depends on load direction, moment arm, speed, duty cycle, lubrication, contamination and required reliability.
Confirm the approved LYDL drawing before machining the shaft, housing or retaining cover.
What Makes RA11008 Different?
Balanced 110 mm Bore
The RA11008 cross roller bearing sits between the 100 mm bore of RA10008 and the 120 mm bore of RA12008.
It is suitable when a 100 mm opening is insufficient but a 136 mm housing for RA12008 would be unnecessarily large.
Only 8 mm Wide
RA11008 provides its 110 mm bore without increasing the width beyond 8 mm.
This leaves more axial space for an encoder, motor, brake, gearbox or cable-routing structure.
Low Rotating Mass
The bearing weighs approximately 0.15 kg. This helps limit moving mass in robot joints, optical heads and precision positioning modules.
Low bearing mass does not remove the need for a rigid housing. The thin outer ring depends on uniform structural support.
Combined-Load Support
The crossed rollers react to radial, bidirectional axial and moment loads in one bearing position.
This can simplify mechanisms that would otherwise require separate radial and thrust bearings.
Typical RA11008 Cross Roller Bearing Applications
The RA11008 cross roller bearing is suitable for:
Hollow-shaft robot joints
Collaborative robot wrists and elbows
Compact servo rotary modules
Semiconductor alignment stages
Optical inspection and scanning systems
Medical positioning mechanisms
Precision measuring instruments
Cable-routing rotary assemblies
The 110 mm bore provides useful space for cables, connectors, pneumatic tubes or optical paths.
Its 126 mm outside diameter also helps control the overall size of the surrounding mechanism.
For additional selection information, visit the LYDL Cross Roller Bearing Guide and Cross Roller Bearing Product Range. Caption: RA11008 supports compact hollow-shaft motion in robot joints, optical stages, inspection systems and precision automation.
Need an RA11008 technical review? Send LYDL your quantity, radial load, axial load, moment load, speed and duty cycle.
Please include the rotating ring, accuracy, clearance or preload, sealing, lubricant and operating temperature.
We will review the RA11008 cross roller bearing configuration and provide a quotation with the controlled drawing.
RA11008 Variants and Suffixes
Suffix conventions can vary between manufacturers. Confirm the complete designation and technical requirements before ordering.
Improves grease retention and contamination protection
RA11008C
Single-split alternative
Structure and availability require drawing confirmation
RA11008CUU
Single-split type with two seals
Confirm sealing drag and operating torque
C0
Standard or positive radial clearance
Generally favors lower rotational resistance
CC0
Controlled negative clearance or preload
Improves rigidity but increases mounting sensitivity
P6T / P5T
Specified rotational-accuracy options
Confirm the rotating ring and inspection method
P4 / P2 custom
LYDL high-precision option
Requires approved accuracy and inspection criteria
UU seals are beneficial where grease retention and environmental protection are important.
Seal contact may increase starting torque. Open bearings can be preferable in clean, enclosed mechanisms requiring minimum resistance.
CC0 preload can improve rigidity and positioning stability. Excessive preload can increase friction, heat and sensitivity to housing error.
An LYDL RA11008 cross roller bearing should be specified from the real operating requirements rather than from the suffix alone.
Choose the RA10008 Cross Roller Bearing when a 100 mm opening is sufficient and the smallest possible housing is preferred.
Select the RA12008 Cross Roller Bearing when a 120 mm through-bore is required.
RA11008 provides a middle-size solution. It adds 10 mm of bore diameter over RA10008 while keeping the outside diameter 10 mm smaller than RA12008.
Installation and Housing Requirements
The thin rings of the RA11008 cross roller bearing closely follow the geometry of the surrounding structure.
Control housing roundness, shaft coaxiality, shoulder perpendicularity and retaining-cover flatness.
Use 113.5 mm as the catalogue maximum shaft-shoulder diameter. Use 120.5 mm as the catalogue minimum housing-shoulder diameter.
Confirm both dimensions against the final LYDL drawing.
Clean all mounting surfaces and remove burrs before assembly. Do not force the bearing into a distorted or misaligned housing.
Tighten the outer-ring retaining cover gradually in a diagonal sequence. Uniform clamping helps prevent local deformation.
After installation, rotate the inner ring slowly. Check starting torque, running torque, noise and runout before connecting the drive.
Abnormal installed torque can result from:
Uneven outer-ring clamping
Insufficient retaining-cover rigidity
Housing roundness error
Misalignment between shaft and housing
Excessive interference
Excessive preload
Seal friction or excessive grease
These installation factors should be checked before concluding that the bearing itself is defective.
Effective Through-Bore Considerations
The nominal bearing bore is 110 mm. The usable opening of the complete mechanism may be smaller.
Shaft shoulders, retaining components, fasteners, cable guides and seals can reduce the available passage.
Designers should check the complete assembly section. The bearing bore alone does not define the final cable-routing diameter.
Cables should also be supported so that they do not rub against the rotating inner ring or interfere with seals.
Accuracy and Rotational Torque
Accuracy requirements should identify the rotating ring and the feature being measured.
The RA11008 design is normally used for inner-ring rotation. Runout inspection should therefore match the final assembly arrangement.
A higher bearing accuracy grade cannot compensate for housing deformation or uneven clamping.
Installed torque should be checked after all retaining screws reach their specified value.
For direct-drive systems, provide the motor’s available starting torque. This helps determine whether seals or CC0 preload are appropriate.
Lubrication and Operating Conditions
Standard RA11008 configurations normally use grease lubrication.
Grease viscosity and fill quantity should match the load, speed, temperature and required rotational resistance.
The published −15°C to +80°C range relates to a standard grease configuration.
Vacuum, cleanroom, low-temperature and high-temperature applications require separate lubricant, seal and material confirmation.
Open bearings require a clean enclosure. Sealed versions improve protection but are not maintenance-free under every duty cycle.
LYDL Manufacturing and Quality Control
LYDL controls ring material, heat treatment, raceway grinding, roller sorting, assembly clearance and final inspection.
Inspection for an RA11008 cross roller bearing can include:
Bore, outside diameter and width
Raceway geometry and surface condition
Radial clearance or preload
Inner-ring rotational runout
Starting and running torque
Noise and rotational smoothness
Seal condition and grease quantity
Marking and packaging inspection
Material certificates, dimensional reports and accuracy records can be supplied when agreed before production.
The bearing receives anti-rust protection and shock-resistant export packaging. Concentrated pressure on the thin outer ring is avoided. Caption: LYDL inspects RA11008 dimensions, clearance, runout and rotational torque before protective export packaging.
Interchange and Cross-Reference Guidance
RA11008 and IKO CRBS1108 share nominal boundary dimensions of 110 × 126 × 8 mm.
Their published load ratings are not identical. Internal roller design, accuracy, clearance and sealing configurations can also differ.
A matching bore, outside diameter and width do not prove complete interchangeability.
Before replacement, provide:
Existing manufacturer and complete model number
All suffixes and accuracy requirements
Shaft and housing drawing
Rotating ring
Loads, moment and speed
Lubrication and environmental conditions
LYDL will compare the existing product with the RA11008 cross roller bearing and issue a controlled drawing for approval.
RA11008 Cross Roller Bearing FAQ
1. When should I choose RA11008 instead of RA10008 or RA12008?
Choose RA11008 when the mechanism needs more than a 100 mm passage but does not require the larger housing envelope of RA12008.
The final choice should also consider load ratings, shoulder dimensions and available structural rigidity.
2. Is the full 110 mm bore available for cables?
Not necessarily. The bearing bore is 110 mm, but the usable passage can be reduced by the shaft, shoulders, fasteners and cable guides.
Check the complete assembly drawing before defining the cable bundle diameter.
3. Can RA11008 be used in a hollow-shaft servo module?
Yes, provided the combined loads, moment, speed, accuracy and torque are suitable.
The 8 mm width leaves valuable axial space for a motor, encoder or brake.
4. Why is the 15 kN static rating higher than the dynamic rating?
Static and dynamic ratings describe different operating conditions and calculation methods.
The 15 kN static rating should not be used as a continuous operating-load limit.
5. Can the outer ring rotate?
RA11008 is normally used with inner-ring rotation because its outer ring is separable and housing-clamped.
For outer-ring rotation, evaluate an integrated-ring RAU design or another appropriate bearing structure.
6. Why can torque change after tightening the retaining cover?
The thin outer ring can follow errors in the cover or housing.
Uneven screw force, excessive interference or housing distortion can change the internal clearance and rotational torque.
7. Can RA11008 directly replace IKO CRBS1108?
The boundary dimensions match, but published load ratings and internal configurations differ.
Compare controlled drawings, clearance, accuracy, seals, lubrication and torque before approving replacement.
8. Should I select C0 or CC0 for a positioning stage?
C0 generally favors lower resistance. CC0 can improve rigidity and reduce internal movement.
The correct choice depends on positioning accuracy, motor torque, temperature and mounting precision.
Request an RA11008 Quotation
Send your application data or existing bearing drawing to receive an RA11008 cross roller bearing quotation.
LYDL can review open, sealed, clearance-controlled and customized precision configurations.
Provide quantity, loads, moment, speed, rotating ring, accuracy, clearance, sealing, lubricant and temperature for an efficient technical review.
ISO 492:2023 — geometrical product specifications and radial-bearing tolerances.
Engineering note: Catalogue values support preliminary selection only. Final life, fit, accuracy, clearance and interchangeability require complete application data and an approved LYDL drawing.
Caption: RA11008 supports compact hollow-shaft motion in robot joints, optical stages, inspection systems and precision automation.
Caption: LYDL inspects RA11008 dimensions, clearance, runout and rotational torque before protective export packaging.