23256 bearing: complete specifications & equivalents
The 23256 is a ISO 15 radial bearing sized 280 x 500 x 176 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 | 500 mm |
| Width B | 176 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 3425 kN |
| Basic static load rating C0 | 4900 kN |
| Fatigue load limit Pu | 365 kN |
| Reference speed (thermal) | 800 rpm |
| Limiting speed (mechanical) | 1100 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 150000 g |
| Manufacturer designation | SKF 23256 CC/W33 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.1 spherical roller bearings |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.1 spherical roller bearings) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.1 spherical 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 & 23200-series range
| Bore d | 11.024 in |
|---|---|
| Outer diameter D | 19.685 in |
| Width B | 6.929 in |
| ISO bore code | 56 |
| Radial section height (D−d)/2 | 110 mm |
| Smallest bore in 23200-series | 90 mm |
| Largest outer diameter in 23200-series | 870 mm |
| Width range across 23200-series | 52.4–310 mm |
| Bore position in 23200-series (smallest first) | 16 of 26 |
| Bore above smallest 23200-series size | 190 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 23256 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; D/B cross-verified against Schaeffler HR1 2022; brand-specific OEM equivalents (NSK/FAG/NTN) pending multi-source data. |
| 23256-CCK-W33 | SKF | full Dimensions and internal design equivalent — standard interchange. | Tapered-bore (1:12) execution on OH2356 adapter sleeve; same ISO 15 envelope, separate order number. |
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 23256 model number is decoded
23256 is a double-row spherical roller bearing in the 23200-series family: two rows of barrel rollers on a common sphered outer raceway, self-aligning under shaft deflection, listed by SKF in SKF catalogue PUB BU/P1 17000. Numbering ties the bearing to its envelope: 23256 means spherical-roller type, dimension series 32, 280 mm bore — which is why the 500×176 mm outline swaps dimensionally with other ISO 15 bearings of the same code. In SKF suffix language, E marks the optimized high-capacity design and CC/W33 the pressed-steel-cage execution with relubrication groove; both are open bearings — the sealed variant carries the 2CS5 suffix and the vibrating-screen execution VA405. Catalogue mass 150000 g for the 280×500×176 mm open execution covers the two pressed-steel cages with a floating guide ring; tapered-bore and sealed variants differ in mass and carry their own order numbers. Drive-on force must go through the ring being fitted: press or induction-heat the inner ring onto the 280 mm shaft (max 120 °C) and never transmit mounting force through the roller complement, or the raceways brinell.
Typical equipment & failure modes
Common applications
- large dredger and marine winch drums
- steel-plant continuous-caster segments
- large induced-draft fan rotors
- SAG and ball-mill drive shafts
Known failure patterns
- raceway fatigue spalling of the sphered outer raceway after extended service above the catalogue L10 rating
- inner-ring raceway spalling from edge loading when misalignment exceeds the self-aligning recovery range
- cage pocket wear or fracture from roller skew at insufficient minimum load or rapid acceleration
- surface distress and smearing when the relubrication interval is exceeded — the W33 groove is only effective if grease actually reaches the roller rows
- seal-lip wear and grease purge loss when an open bearing is run without functioning housing seals
Selection pitfalls — read before you substitute
- At 280 mm bore the ring mass makes cocking during mounting a real risk; guide the bearing square, confirm seat contact around the full circumference, and re-check the self-aligning swing after the housing cap is torqued down.
- The 23200-series series at 280 mm bore (500×176 mm) adds still more width for shock-loaded and vibratory loads; it does not interchange with a 231 bearing of the same bore because the 176 mm width changes abutment spacing, even though the 500 mm OD matches.
- Catalogue reference speed and limiting speed are different limits: the 800 r/min reference is a thermal criterion under load, while the 1,100 r/min limiting value is the mechanical ceiling — observe both.
- Catalogue reference speed and limiting speed are different limits: the 800 r/min reference is a thermal criterion under load, while the 1,100 r/min limiting value is the mechanical ceiling — observe both.
- The 3425/4900 kN ratings are SKF catalogue values for this exact execution (23256 CC/W33); SKF can revise internal geometry without changing the order number, so keep the catalogue version (SKF catalogue PUB BU/P1 17000) with the specification and re-verify for critical drives.
- SKF lists several executions of 23256 (cylindrical bore as listed, tapered-bore 23256 CCK/W33 variant, plus sealed and vibrating-screen options in the same envelope); they are not interchangeable order numbers — quote the full 23256 CC/W33 designation when purchasing.
Frequently asked questions
What are the dimensions and catalogue data of 23256?
The 23256 CC/W33 is a double-row spherical roller bearing with 280 mm bore, 500 mm outer diameter and 176 mm width (11.024 × 19.685 × 6.929 in) per ISO 15. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 3425 kN, C0 4900 kN, fatigue load limit Pu 365 kN, reference speed 800 r/min, limiting speed 1,100 r/min, mass about 150000 g. It is an open, self-aligning bearing with two pressed-steel cages with a floating guide ring.
How does the 23256 bore code work?
The last two digits of 23256 are bore code 56, so 56 × 5 = 280 mm bore. The 500 mm OD and 176 mm width come from the ISO 15 dimension-series plan (dimension series 32 (medium OD, extra wide)), shared with other spherical roller bearings of the same code.
What does the CC/W33 suffix mean on 23256?
CC denotes two pressed-steel cages with a floating guide ring between the roller rows, and W33 adds an annular groove plus three lubrication holes in the outer ring for relubrication. CCK/W33 is the 1:12 tapered-bore counterpart.
Can 23256 accommodate misalignment and axial load?
Yes on both counts. The sphered outer raceway lets the bearing self-align ≈ 0.5–2.5° depending on series, absorbing shaft deflection and housing-seat errors. The two barrel-roller rows also carry bidirectional axial load in addition to heavy radial load — this is the key difference from cylindrical roller bearings, which take no axial load.
When should the tapered-bore 23256K variant be used instead?
Choose the K (1:12 tapered bore) variant when the bearing must seat on an adapter or withdrawal sleeve — typical for long shafts, frequent dismounting, or stepped shafts where machining a precision journal is impractical. Sleeve mounting requires measuring clearance reduction or axial drive-up, not nut torque. The cylindrical-bore 23256 listed here seats directly on a machined journal.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 9.1 spherical roller bearings on 2026-09-26. Read our editorial & correction policy.