C3972-KM bearing: complete specifications & equivalents
The C3972-KM is a ISO 15 radial bearing sized 360 x 480 x 90 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 360 mm |
| Outer diameter D | 480 mm |
| Width B | 90 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 1760 kN |
| Basic static load rating C0 | 3250 kN |
| Fatigue load limit Pu | 245 kN |
| Reference speed (thermal) | 1000 rpm |
| Limiting speed (mechanical) | 1400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 45000 g |
| Manufacturer designation | C 3972 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 & C3900-series range
| Bore d | 14.173 in |
|---|---|
| Outer diameter D | 18.898 in |
| Width B | 3.543 in |
| ISO bore code | 72 |
| Radial section height (D−d)/2 | 60 mm |
| Smallest bore in C3900-series | 360 mm |
| Largest outer diameter in C3900-series | 2180 mm |
| Width range across C3900-series | 90–355 mm |
| Bore position in C3900-series (smallest first) | 1 of 15 |
| Bore above smallest C3900-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| C3972-M | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 360×480×90 mm ISO 15 envelope and equivalent catalogue C/C0; C 3972 M is the cylindrical-bore M brass-caged execution of this size — boundary dimensions interchangeable, only mounting and cage execution differ. |
| 23972 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 360×480×90 mm envelope as the SKF spherical roller bearing SKF 23972 CC/W33, but catalogue C/C0 differ (1760/3250 kN vs 1456/2750 kN) — and the functions differ: spherical locates axially, CARB floats. Pair them; never swap one-for-one. |
| 23972-CCK-W33 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 360×480×90 mm envelope as the SKF spherical roller bearing SKF 23972 CCK/W33, but catalogue C/C0 differ (1760/3250 kN vs 1456/2750 kN) — and the functions differ: spherical locates axially, CARB floats. Pair them; never swap one-for-one. |
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 C3972-KM model number is decoded
In SKF catalogue PUB BU/P1 17000, C 3972 KM denotes a toroidal roller bearing whose 90 mm long rollers crown at both ends: the contact accepts angular misalignment while the ring positions float, which is why CARB bearings are specified at the free shaft end. The designation C 3972 KM separates into C (CARB), 39 (dimension series), 72 (360 mm bore) and KM (tapered 1:12 bore for adapter (H) sleeve mounting, machined brass M cage); envelope 360×480×90 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 360 mm shaft deflects; the 1,000 r/min reference and 1,400 r/min limiting speed are both catalogue values. The 45000 g mass over the 360×480×90 mm envelope yields about 4.89 kN dynamic per millimetre of bore — the long toroidal rollers give this family its radial capacity density. After fitting, confirm the inner ring can be pushed axially by hand through the catalogue displacement range; a ring that will not slide means the position is locked and will preload in service.
Typical equipment & failure modes
Common applications
- 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
- vibrating screen exciters fitted with the VE240 tolerance execution
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
- condensation pitting in machines that run intermittently in humid environments
- grease churning and overheating when a high-speed thrust position is over-packed
Selection pitfalls — read before you substitute
- Above 200 mm bore these bearings weigh tens of kilograms (45 kg here) — lifting gear and induction heating are mandatory, and a cocked ring scores the toroidal raceway before start-up.
- Reference and limiting speeds are different limits: the 1,000 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 1760/3250 kN ratings belong to this exact execution (C 3972 KM); VE240 vibrating-screen variants and sealed 2CS/2NS variants have their own figures even at the same envelope.
- Never use C 3972 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.
- Tapered-bore K executions mount on adapter sleeves (1:12) and K30 on withdrawal sleeves (1:30) — the 360 mm bore changes the sleeve family, and the drive-up procedure differs accordingly.
- The 1760/3250 kN ratings and 45000 g mass are SKF catalogue values transcribed from ch. 10.1 of PUB BU/P1 17000 (PDF table page 864); 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 3972 KM?
A C 3972 KM measures 360 mm bore × 480 mm outside diameter × 90 mm width (14.173 × 18.898 × 3.543 in). From SKF catalogue PUB BU/P1 17000: dynamic C 1760 kN, static C0 3250 kN, fatigue limit Pu 245 kN, reference speed 1,000 r/min, limiting speed 1,400 r/min, mass about 45000 g.
Can a CARB bearing like C 3972 KM locate the shaft axially?
No — that is the defining feature. C 3972 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 3972 KM designation read?
C = CARB toroidal family; 39 = dimension series; 72 = 360 mm bore (code 72 × 5); 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 (1760 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 3972 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.