C3056 bearing: complete specifications & equivalents
The C3056 is a ISO 15 radial bearing sized 280 x 420 x 106 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 280 mm |
| Outer diameter D | 420 mm |
| Width B | 106 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 1860 kN |
| Basic static load rating C0 | 3100 kN |
| Fatigue load limit Pu | 250 kN |
| Reference speed (thermal) | 1200 rpm |
| Limiting speed (mechanical) | 1600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 50500 g |
| Manufacturer designation | C 3056 |
| 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 | 11.024 in |
|---|---|
| Outer diameter D | 16.535 in |
| Width B | 4.173 in |
| ISO bore code | 56 |
| Radial section height (D−d)/2 | 70 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) | 10 of 33 |
| Bore above smallest C3000-series size | 160 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| C3056-K | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 280×420×106 mm ISO 15 envelope and equivalent catalogue C/C0; C 3056 K is the 1:12 tapered-bore K steel-caged execution of this size — boundary dimensions interchangeable, only mounting and cage execution differ. |
| 23056 | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (280×420×106 mm) SKF spherical roller bearing SKF 23056 CC/W33 with ratings within 10 % — not a drop-in substitute: SKF 23056 CC/W33 locates the shaft axially while the CARB bearing must float; the two are designed to run as a locating/non-locating pair. |
| 23056-CCK-W33 | SKF | full Dimensions and internal design equivalent — standard interchange. | Envelope-identical (280×420×106 mm) SKF spherical roller bearing SKF 23056 CCK/W33 with ratings within 10 % — not a drop-in substitute: SKF 23056 CCK/W33 locates the shaft axially while the CARB bearing must float; the two are designed to run as a locating/non-locating pair. |
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 C3056 model number is decoded
C 3056 is the dimension series 30 CARB toroidal roller bearings member of the CARB range: 280 mm bore, 420 mm OD, 106 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 3056 is the steel-caged cylindrical-bore bearing, K (or K30) makes the bore tapered for sleeve mounting, and the cage/seal letters follow — here the bare number. The cylindrical 280 mm bore mounts directly on a machined seat; the outer ring takes a loose housing fit so the bearing can float axially. The same size is listed in both bore executions, and the boundary dimensions 280×420×106 mm are identical — only the mounting method changes. The 50500 g mass over the 280×420×106 mm envelope yields about 6.64 kN dynamic per millimetre of bore — the long toroidal rollers give this family its radial capacity density. 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 106 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
- brass cage pocket wear under marginal lubrication in the large-bore M/MB executions
- condensation pitting in machines that run intermittently in humid environments
- oil starvation at the sliding contact zones of large spherical roller thrust bearings on forced-feed trips
Selection pitfalls — read before you substitute
- Above 200 mm bore these bearings weigh tens of kilograms (50.5 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 3056 must float; the two are designed to be used as a pair.
- Never use C 3056 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 1,200 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 1860/3100 kN ratings belong to this exact execution (C 3056); VE240 vibrating-screen variants and sealed 2CS/2NS variants have their own figures even at the same envelope.
- The 1860/3100 kN ratings and 50500 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
Which dimensions does the C 3056 have?
A C 3056 measures 280 mm bore × 420 mm outside diameter × 106 mm width (11.024 × 16.535 × 4.173 in). From SKF catalogue PUB BU/P1 17000: dynamic C 1860 kN, static C0 3100 kN, fatigue limit Pu 250 kN, reference speed 1,200 r/min, limiting speed 1,600 r/min, mass about 50500 g.
What does C 3056 mean in SKF part numbering?
C marks CARB; 30 the dimension series; the size code gives 280 mm bore; the bare number is the execution (cylindrical bore for direct shaft fitting, pressed steel cage). The envelope follows ISO 15 and matches spherical roller bearing outlines, but the functions differ.
Why is C 3056 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.
Is the C 3056 sealed?
No, it is an open execution relying on the housing seals; relubrication follows the groove/hole features of the size.
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.