C30-670-KM bearing: complete specifications & equivalents
The C30-670-KM is a ISO 15 radial bearing sized 670 x 980 x 230 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 670 mm |
| Outer diameter D | 980 mm |
| Width B | 230 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 8150 kN |
| Basic static load rating C0 | 16300 kN |
| Fatigue load limit Pu | 1000 kN |
| Reference speed (thermal) | 430 rpm |
| Limiting speed (mechanical) | 600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 590000 g |
| Manufacturer designation | C 30/670 KM |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings) · extracted 2026-09-27
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & C3000-series range
| Bore d | 26.378 in |
|---|---|
| Outer diameter D | 38.583 in |
| Width B | 9.055 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 155 mm |
| Smallest bore in C3000-series | 120 mm |
| Largest outer diameter in C3000-series | 1420 mm |
| Width range across C3000-series | 46–308 mm |
| Bore position in C3000-series (smallest first) | 26 of 33 |
| Bore above smallest C3000-series size | 550 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| C30-670-M | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 670×980×230 mm ISO 15 envelope and equivalent catalogue C/C0; C 30/670 M is the cylindrical-bore M brass-caged execution of this size — boundary dimensions interchangeable, only mounting and cage execution differ. |
Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.
How the C30-670-KM model number is decoded
For long shafts that grow thermally, SKF supplies C 30/670 KM: the toroidal rollers allow the 670 mm inner ring to displace axially without induced thrust, while still accommodating shaft deflection like a spherical bearing. In C 30/670 KM the 30 dimension series fixes the 980 mm OD and 230 mm width around the 670 mm bore (the bore is written directly after the slash (no bore code)); the suffix KM then selects the tapered 1:12 bore for adapter (H) sleeve mounting, machined brass M cage. The KM suffix is a one-piece machined brass cage centred on the rollers, supplied for the 670 mm and larger sizes needing robust guidance under heavy load. Float capacity is a selection criterion: the catalogue lists the permissible axial displacement (s) for the 230 mm wide set; size the free-end housing so thermal growth stays within it, not just inside the overall width. Seat tolerances follow the ISO 15 recommendation for the heavy-loaded position — the 980 mm outer ring typically takes a loose housing fit to preserve float, and the rings must be supported across their full faces.
Typical equipment & failure modes
Common applications
- paper machine drying cylinders and calender rolls with long, thermally expanding shafts
- continuous-caster guide rolls and slab-caster segments under heat growth
- vibrating screen exciters fitted with the VE240 tolerance execution
- long fan and kiln main shafts where the free end must float without thrust load
Known failure patterns
- raceway spalling once the catalogue L10 life is exceeded or after sustained overload
- thermal preloading when a shaft is located at both ends and growth has nowhere to go
- PA66 cage (TN9) softening when the sustained temperature passes the polymer limit
- false brinelling and rust-red witness marks on standby machines under external vibration
- abrasive paste forming as dust bypasses the housing seals into the open washer set
Selection pitfalls — read before you substitute
- At 670 mm bore the 590 kg mass and 230 mm width make seating geometry dominant: sphered-washer seats and oil flow must be verified in place, not just on the drawing.
- Reference and limiting speeds are different limits: the 430 r/min reference speed is the thermal criterion under load, the limiting value is the mechanical ceiling; observe the reference under load unless the arrangement calculation says otherwise.
- The quoted 8150/16300 kN ratings belong to this exact execution (C 30/670 KM); VE240 vibrating-screen variants and sealed 2CS/2NS variants have their own figures even at the same envelope.
- Tapered-bore K executions mount on adapter sleeves (1:12) and K30 on withdrawal sleeves (1:30) — the 670 mm bore changes the sleeve family, and the drive-up procedure differs accordingly.
- Never use C 30/670 KM as the locating bearing: it carries no axial load by design — the arrangement needs a separate locating spherical, tapered or angular bearing facing the thrust.
- The 8150/16300 kN ratings and 590000 g mass are SKF catalogue values transcribed from ch. 10.1 of PUB BU/P1 17000 (PDF table page 868); mounting data — axial displacement (s) and seating details — appears in the running text because the structured record carries the boundary envelope only.
Frequently asked questions
What are the dimensions and ratings of the C 30/670 KM?
A C 30/670 KM measures 670 mm bore × 980 mm outside diameter × 230 mm width (26.378 × 38.583 × 9.055 in). From SKF catalogue PUB BU/P1 17000: dynamic C 8150 kN, static C0 16300 kN, fatigue limit Pu 1000 kN, reference speed 430 r/min, limiting speed 600 r/min, mass about 590000 g.
Can a CARB bearing like C 30/670 KM locate the shaft axially?
No — that is the defining feature. C 30/670 KM deliberately allows the inner ring to float axially inside the outer ring while the toroidal rollers self-align. It must be paired with a separate locating bearing (spherical, tapered or angular contact) that takes 100 % of the thrust.
How is the C 30/670 KM designation read?
C = CARB toroidal family; 30 = dimension series; 670 mm (slash-size) = 670 mm bore (the bore is written directly after the slash (no bore code)); suffix KM selects tapered 1:12 bore for adapter (H) sleeve mounting, machined brass M cage. K is a 1:12 tapered bore for an adapter sleeve, K30 a 1:30 bore for a withdrawal sleeve.
What is the difference between V and TN9 CARB executions?
V is the full-complement execution with no cage — more rollers, higher C (8150 kN here) but a lower speed ceiling and no thermal reference speed. TN9 is the glass-fibre PA66 caged execution, faster and quieter at somewhat lower load. C 30/670 KM is the tapered 1:12 bore for adapter (H) sleeve mounting, machined brass M cage.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 10.1 CARB toroidal roller bearings on 2026-09-27. Read our editorial & correction policy.