RKS 061.25.1204 slewing bearing
Quenched & Tempered Hardness: HB 229–269
Raceway Surface Hardness: HRC 55–62
Hardened Layer Depth: ≥ 4.5 mm (Deepened for 25-series wide type)
Seal Type: Double-lip NBR seal (both sides)
Operating Temperature: -25°C to +70°C
Precision Class: P0 (Standard) / P6 / P5 (Customizable)
Gear Precision: ISO 1328 Gr.9 (Standard) / Gr.7 (Customizable)
Axial Clearance: ≤ 0.40 mm (Standard) / ≤ 0.20 mm (Preload customizable)
Radial Clearance: ≤ 0.35 mm (Standard) / ≤ 0.18 mm (Preload customizable)
Factory Inspection: 100% ultrasonic testing + full dimensional inspection + roundness measurement
Special Inspection: Lifting fixture required for large components (154 kg) to ensure no deformation of the mounting surface
- Product Description
RKS 061.25.1204 Slewing Bearing – Heavy-Duty Solution for Tower Cranes and Industrial Rotating Equipment
The RKS 061.25.1204 Slewing Bearing is a heavy-duty, externally-geared single-row ball bearing designed for applications demanding high static load capacity and structural robustness. Featuring a 1338 mm outer diameter, 68 mm profile height, and 25 mm ball diameter, this bearing delivers 3990 KN axial static load capacity—47% higher than comparable 20-series models. With module 10 external gearing (131 teeth), 16 mm through-bolt holes (45 per ring), and induction-hardened raceways (HRC 55-62), the product is engineered for tower crane slewing mechanisms, crawler cranes, and other heavy excavator requiring long-term reliability under tilting moments.
Technical Specifications
Dimensional Parameters
Parameter | Value | Unit |
Outer Diameter (D) | 1338 | mm |
Outer Ring Step Diameter (D₁) | 1207.5 | mm |
Inner Diameter (d) | 1119 | mm |
Inner Ring Step Diameter (d₁) | 1200.5 | mm |
Total Height (H) | 68 | mm |
Ball Diameter | 25 | mm |
Weight | 154 | kg |
Gear Parameters
Parameter | Value | Unit |
Pitch Circle Diameter (d₀₁) | 1310 | mm |
Module (m) | 10 | — |
Number of Teeth (z) | 131 | — |
Pressure Angle | 20° | — |
Profile Shift Coefficient (x·m) | +5 | mm |
Addendum Reduction Coefficient (k·m) | -1 | mm |
Tooth Width (b) | 65 | mm |
Normal Permissible Tooth Force | 45 | KN |
Maximum Permissible Tooth Force | 130 | KN |
Gear Precision | ISO 1328 Gr.9 (Standard) / Gr.7 (Customizable) | — |
Mounting Bolt Holes
Parameter | Outer Ring | Inner Ring | Unit |
Bolt Circle Diameter | Je = 1257 | Ji = 1151 | mm |
Bolt Hole Specification | Ke = 16 | Ki = 16 | mm |
Number of Bolts | Ne = 45 | Ni = 45 | — |
Bolt Grade | Grade 10.9 (Standard) / 12.9 (Customizable) | Same | — |
Note: The 16 mm through-holes (for M16 bolts) provide significantly higher mounting strength compared to the 20-series M12 holes. Consult installation guidelines for proper torque values.
Load Performance
Parameter | Value | Unit |
Axial Dynamic Load (C) | 508 | KN |
Axial Static Load (C₀) | 3990 | KN |
Raceway Load Curve Number | r1 | — |
Bolt Load Curve Number | b1 | — |
Safety Factor (Tower Crane Application) | fs ≥ 1.45 | — |
Material & Quality Standards
Material Composition
Component | Outer/Inner Ring | Rolling Elements |
Material Grade | 42CrMo (EN 1.7225) / 50Mn | 100Cr6 (GCr15) |
Quenched & Tempered Hardness | HB 229-269 | — |
Raceway Surface Hardness | HRC 55-62 | HRC 60-64 |
Hardened Layer Depth | ≥ 4.5 mm (Deepened for 25-series) | — |
Seal Type | Double-lip NBR seal (both sides) | — |
Operating Temperature | -25°C to +70°C | — |
Precision & Inspection
Parameter | Value |
Precision Class | P0 (Standard) / P6 / P5 (Customizable) |
Gear Precision | ISO 1328 Gr.9 (Standard) / Gr.7 (Customizable) |
Axial Clearance | ≤ 0.40 mm (Standard) / ≤ 0.20 mm (Preload option) |
Radial Clearance | ≤ 0.35 mm (Standard) / ≤ 0.18 mm (Preload option) |
Factory Inspection | 100% ultrasonic testing + full dimensional inspection + roundness measurement |
Special Inspection | Lifting fixture required for 154 kg components to prevent mounting surface deformation |
061.25 Series vs 061.20 Series: Why Choose the Heavy-Duty 25 Series?
The 061 slewing bearing series comes in two load classes distinguished by ball diameter:
Feature | 061.20 Series (Light/Medium) | 061.25 Series (Heavy Duty) |
Ball Diameter | 20 mm | 25 mm (+25%) |
Profile Height (H) | 56 mm | 68 mm (+21%) |
Maximum OD | 1198.4 mm (1094) | 1901 mm (1754) |
Max Static Load | 2710 KN | 3990 KN (+47% for comparable size) |
Bolt Size | M12 | 16 mm |
Gear Module Range | 5, 6, 8 | 8, 10, 12, 14 |
Typical Applications | Excavators, truck cranes, welding positioners | Tower cranes, heavy crawler cranes, wind turbines, offshore cranes |
The 061.25.1204 sits at the entry point of the 25 series, offering the heavy-duty raceway and gear capacity of the 25 mm ball class while maintaining a relatively compact 1338 mm outer diameter. If your application is outgrowing the 061.20.1094 (56 mm profile, 2710 KN static load), stepping up to the RKS 061.25.1204 slewing bearing (68 mm profile, 3990 KN static load) provides 47% higher static capacity with only a 12 mm increase in height.
Primary Application: Tower Crane Slewing Mechanism
The 061.25.1204 is most commonly specified as the main slewing ring in tower cranes. Its 1338 mm outer diameter, 68 mm profile height, and module 10 external gear with 131 teeth make it a direct fit for mid-to-large tower crane models from major OEMs including Liebherr, Potain, Terex, Zoomlion, and XCMG. Each tower crane uses one slewing bearing driven by multiple slew drives (typically 2–4 pinions). With millions of tower cranes globally requiring bearing replacement every 5-8 years, the standardized 1204 designation ensures worldwide OEM compatibility.
Why Tower Crane Operators Choose the 25 Series:
· 47% higher static load capacity vs the 20 series—critical for high tilting moments generated by long jib extensions
· Module 10 gear with 131 teeth—provides optimal gear ratio for standard tower crane slewing motor pinions
· 16 mm bolt holes—matching the structural bolt specification of tower crane mast sections
· 68 mm profile—compact enough to fit within standard tower crane turntable assemblies
Other Industrial Applications
Whether you need a tower crane slewing bearing 1338mm, large crawler crane slewing ring, portal crane slewing bearing heavy duty, wind turbine yaw bearing 1338mm 68mm, mining stacker reclaimer slewing bearing, offshore platform main crane slewing ring, giant ferris wheel main slewing bearing, or floating crane slewing bearing, the 061.25.1204 offers proven performance across demanding industrial sectors:
Industry | Equipment | Why 1204 Fits |
Heavy Crawler Cranes | 100-200 ton crawler crane swing bearing | High tilting moment capacity; external gear for direct hydraulic motor drive |
Wind Turbines | 2-3 MW yaw bearing system | Large diameter + high static load for nacelle rotation under wind load |
Port & Portal Cranes | Gantry crane slewing mechanism | Corrosion-resistant surface treatment options for marine environments |
Offshore Platforms | Main deck crane slewing ring | Certified material traceability (EN 10204 3.1) for offshore safety requirements |
Mining Stacker/Reclaimers | Boom slewing bearing | Continuous rotation under heavy dust load; induction-hardened raceways for wear resistance |
Floating Cranes | Barge-mounted crane turntable | High dynamic load capacity; sealed raceway for saltwater splash protection |
Certification
FAQ
Q: Can the 061.25.1204 replace an 061.20.1094 bearing?
No. Despite both being 061-series models, the 25-series has a larger envelope (OD 1338 mm vs 1198 mm), taller profile (68 mm vs 56 mm), different bolt hole patterns (16 mm vs M12), and a larger module gear (10 vs 8). You will need to verify mounting space and gear compatibility.
Q: What is the lead time for standard vs custom configurations?
In-stock products ship within 7-15 days. Custom setups take 4-6 weeks, depending on intricacy.
Q: Is preload recommended for tower crane applications?
Standard axial clearance (≤ 0.40 mm) is sufficient for most tower cranes. Preload (≤ 0.20 mm) may be specified for high-precision applications or reduced clearance requirements.
Contact Us
For the RKS 061.25.1204 slewing bearing, if you have technical specifications, custom configurations, or sample inquiries, reach out to mia@hgb-bearing.com to confirm compatibility and delivery schedules for your next project.
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