C31-530-KM bearing: complete specifications & equivalents
The C31-530-KM is a ISO 15 radial bearing sized 530 x 870 x 272 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 530 mm |
| Outer diameter D | 870 mm |
| Width B | 272 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 8800 kN |
| Basic static load rating C0 | 15600 kN |
| Fatigue load limit Pu | 1020 kN |
| Reference speed (thermal) | 500 rpm |
| Limiting speed (mechanical) | 670 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 636000 g |
| Manufacturer designation | C 31/530 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 & C3100-series range
| Bore d | 20.866 in |
|---|---|
| Outer diameter D | 34.252 in |
| Width B | 10.709 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 170 mm |
| Smallest bore in C3100-series | 100 mm |
| Largest outer diameter in C3100-series | 1580 mm |
| Width range across C3100-series | 52–462 mm |
| Bore position in C3100-series (smallest first) | 22 of 28 |
| Bore above smallest C3100-series size | 430 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| C31-530-M | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 530×870×272 mm ISO 15 envelope and equivalent catalogue C/C0; C 31/530 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 C31-530-KM model number is decoded
The CARB bearing C 31/530 KM combines the self-aligning behaviour of a spherical roller bearing with the axial freedom of a cylindrical bearing in one 530 mm bore, 870 mm outside diameter, 272 mm wide unit rated 8800 kN dynamic. The designation C 31/530 KM separates into C (CARB), 31 (dimension series), 530 mm (slash-size) (530 mm bore — bore 530 mm is written directly after the slash) and KM (tapered 1:12 bore for adapter (H) sleeve mounting, machined brass M cage); envelope 530×870×272 mm follows the ISO 15 plan. The open execution relies on the housing seals and lubrication system, fed through groove/hole features on the large sizes. Explorer-class heat treatment and the crowned roller profile keep edge stress down when the 530 mm shaft deflects; the 500 r/min reference and 670 r/min limiting speed are both catalogue values. Pairing rule: use the CARB bearing opposite one locating spherical or tapered bearing — never at both shaft ends — and check the locating bearing takes 100 % of the thrust, since C 31/530 KM deliberately carries none. Seat tolerances follow the ISO 15 recommendation for the heavy-loaded position — the 870 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
- heavy industrial gearbox layshafts used as the non-locating position
- winder and reel drums in paper and steel strip plants
- paper machine drying cylinders and calender rolls with long, thermally expanding shafts
- continuous-caster guide rolls and slab-caster segments under heat growth
Known failure patterns
- raceway spalling once the catalogue L10 life is exceeded or after sustained overload
- edge loading and premature spalling when the CARB position is blocked from its designed axial float
- brass cage pocket wear under marginal lubrication in the large-bore M/MB executions
- false brinelling and rust-red witness marks on standby machines under external vibration
- grease churning and overheating when a high-speed thrust position is over-packed
Selection pitfalls — read before you substitute
- At 530 mm bore the 636 kg mass and 272 mm width make seating geometry dominant: sphered-washer seats and oil flow must be verified in place, not just on the drawing.
- Do not block the axial displacement in the drawing: housing covers, labyrinth rings and snap rings must leave the catalogue float (s) free, or the bearing silently becomes a poorly located fixed bearing.
- Envelope-identical spherical roller bearings (same ISO 15 d×D×B) are not drop-in equivalents — they locate the shaft axially, while C 31/530 KM must float; the two are designed to be used as a pair.
- The quoted 8800/15600 kN ratings belong to this exact execution (C 31/530 KM); VE240 vibrating-screen variants and sealed 2CS/2NS variants have their own figures even at the same envelope.
- Never use C 31/530 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 8800/15600 kN ratings and 636000 g mass are SKF catalogue values transcribed from ch. 10.1 of PUB BU/P1 17000 (PDF table page 866); 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
How is C 31/530 KM mounted?
The tapered 1:12 bore mounts on an adapter (H) sleeve with a defined drive-up; heat the bearing to max 120 °C when fitting, support full ring faces, and verify axial float afterwards.
What are the dimensions and ratings of the C 31/530 KM?
A C 31/530 KM measures 530 mm bore × 870 mm outside diameter × 272 mm width (20.866 × 34.252 × 10.709 in). From SKF catalogue PUB BU/P1 17000: dynamic C 8800 kN, static C0 15600 kN, fatigue limit Pu 1020 kN, reference speed 500 r/min, limiting speed 670 r/min, mass about 636000 g.
Can a CARB bearing like C 31/530 KM locate the shaft axially?
No — that is the defining feature. C 31/530 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 31/530 KM designation read?
C = CARB toroidal family; 31 = dimension series; 530 mm (slash-size) = 530 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.
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.