23988 bearing: complete specifications & equivalents
The 23988 is a ISO 15 radial bearing sized 440 x 600 x 118 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 440 mm |
| Outer diameter D | 600 mm |
| Width B | 118 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 2506 kN |
| Basic static load rating C0 | 4900 kN |
| Fatigue load limit Pu | 345 kN |
| Reference speed (thermal) | 950 rpm |
| Limiting speed (mechanical) | 1000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 99500 g |
| Manufacturer designation | SKF 23988 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 & 23900-series range
| Bore d | 17.323 in |
|---|---|
| Outer diameter D | 23.622 in |
| Width B | 4.646 in |
| ISO bore code | 88 |
| Radial section height (D−d)/2 | 80 mm |
| Smallest bore in 23900-series | 180 mm |
| Largest outer diameter in 23900-series | 650 mm |
| Width range across 23900-series | 52–128 mm |
| Bore position in 23900-series (smallest first) | 15 of 17 |
| Bore above smallest 23900-series size | 260 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 23988 | 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. |
| 23988-CCK-W33 | SKF | full Dimensions and internal design equivalent — standard interchange. | Tapered-bore (1:12) execution on OH3988 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 23988 model number is decoded
Ordering number 23988 CC/W33 in SKF catalogue PUB BU/P1 17000 denotes a double-row spherical roller bearing for a 440 mm shaft, dimension series 39 (compact OD, narrow), with open execution and two pressed-steel cages with a floating guide ring. The code breaks down as type digit 2 (double-row spherical roller), dimension series 39 (dimension series 39 (compact OD, narrow)), and bore code 88 = 440 mm; dimensions 440×600×118 mm therefore match the ISO 15 envelope. SKF basic executions here are E or CC/W33; specialist suffixes change the bearing materially — VA405 for vibrating screens (C4 clearance, surface-hardened cage), 2CS5 for the sealed variant — and must be quoted in full when ordering. The 345 kN Pu figure feeds the adjusted-life equation at contaminated or partial-film conditions, and the 1.96 C0/C balance shows this execution is tuned to heavy radial-plus-axial duty with misalignment tolerance. Spherical roller bearings are routinely specified with C3 clearance because the tight inner-ring fit and inner/outer temperature gradient eat into the CN running clearance — check the residual clearance after mounting with feeler gauges.
Typical equipment & failure modes
Common applications
- steel-plant continuous-caster segments
- large induced-draft fan rotors
- SAG and ball-mill drive shafts
- large mining crusher main 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
- false brinelling on standby machines exposed to external vibration
Selection pitfalls — read before you substitute
- At 440 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 23900-series series at 440 mm bore (600×118 mm) is the slim-OD envelope: it buys radial space but gives up capacity against a 222-series bearing of the same bore — confirm the L10 margin before downsizing into it.
- Shaft and housing fillets must clear the bearing chamfer so the 118 mm-wide rings seat square; use an undercut or withdrawal groove rather than an oversized radius that locks on the ring face.
- The self-aligning feature is not a license to ignore alignment: beyond ≈ 0.5–2.5° (series-dependent) the edge loading eats the fatigue margin, and seal drag grows as the rings tilt.
- The 2506/4900 kN ratings are SKF catalogue values for this exact execution (23988 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 23988 (cylindrical bore as listed, tapered-bore 23988 CCK/W33 variant, plus sealed and vibrating-screen options in the same envelope); they are not interchangeable order numbers — quote the full 23988 CC/W33 designation when purchasing.
Frequently asked questions
What are the dimensions and catalogue data of 23988?
The 23988 CC/W33 is a double-row spherical roller bearing with 440 mm bore, 600 mm outer diameter and 118 mm width (17.323 × 23.622 × 4.646 in) per ISO 15. From SKF catalogue PUB BU/P1 17000: basic dynamic load rating C 2506 kN, C0 4900 kN, fatigue load limit Pu 345 kN, reference speed 950 r/min, limiting speed 1,000 r/min, mass about 99500 g. It is an open, self-aligning bearing with two pressed-steel cages with a floating guide ring.
How does the 23988 bore code work?
The last two digits of 23988 are bore code 88, so 88 × 5 = 440 mm bore. The 600 mm OD and 118 mm width come from the ISO 15 dimension-series plan (dimension series 39 (compact OD, narrow)), shared with other spherical roller bearings of the same code.
What does the CC/W33 suffix mean on 23988?
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 23988 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 23988K 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 23988 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.