C3972-M bearing: complete specifications & equivalents
The C3972-M 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 M |
| 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-KM | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 360×480×90 mm ISO 15 envelope and equivalent catalogue C/C0; C 3972 KM is the 1:12 tapered-bore K 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-M model number is decoded
C 3972 M is the dimension series 39 CARB toroidal roller bearings member of the CARB range: 360 mm bore, 480 mm OD, 90 mm width, with the asymmetrical-looking toroidal roller set that defines the CARB principle. SKF builds the CARB order number from size plus execution: the bare number C 3972 is the brass-caged cylindrical-bore bearing, K (or K30) makes the bore tapered for sleeve mounting, and the cage/seal letters follow — here M. The M suffix is a one-piece machined brass cage centred on the rollers, supplied for the 360 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 90 mm wide set; size the free-end housing so thermal growth stays within it, not just inside the overall width. Open executions accept relubrication — route it through the outer-ring groove on sizes that have one and purge stale grease at service intervals. Grease through the annular groove features where provided; on open executions feed lubricant past the long roller set at assembly, since the 90 mm wide cavity does not fill itself.
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
- roller-end and flange smearing after lubricant starvation at the long roller contacts
- roller skew and cage damage after the bearing is clamped solid between shaft and housing shoulders
- PA66 cage (TN9) softening when the sustained temperature passes the polymer limit
- hard-particle indentation where oil or grease filtration is inadequate
- abrasive paste forming as dust bypasses the housing seals into the open washer set
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.
- Envelope-identical spherical roller bearings (same ISO 15 d×D×B) are not drop-in equivalents — they locate the shaft axially, while C 3972 M must float; the two are designed to be used as a pair.
- Never use C 3972 M 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.
- 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 M); VE240 vibrating-screen variants and sealed 2CS/2NS variants have their own figures even at the same envelope.
- 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 fails first on a misapplied CARB bearing?
Blocking the designed axial float — clamping the free end or locating both shaft ends — turns thermal growth into edge loading and spalls the toroidal raceways. Cage damage and ordinary fatigue follow overload or dry running.
Which dimensions does the C 3972 M have?
A C 3972 M 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.
What does C 3972 M mean in SKF part numbering?
C marks CARB; 39 the dimension series; the size code gives 360 mm bore; M is the execution (cylindrical bore for direct shaft fitting, machined brass M cage). The envelope follows ISO 15 and matches spherical roller bearing outlines, but the functions differ.
Why is C 3972 M used opposite a spherical roller bearing?
The spherical bearing locates the shaft and takes thrust; the CARB bearing at the other end self-aligns but floats, absorbing thermal expansion without inducing axial load. The pair is standard on paper machine drying cylinders and long caster rolls.
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.