23988-NTN bearing: complete specifications & equivalents
The 23988-NTN 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 | NTN |
| 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 |
| Basic dynamic load rating C | 2260 kN |
| Basic static load rating C0 | 4700 kN |
| Fatigue load limit Pu | 325 kN |
| Limiting speed (mechanical) | 500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 101000 g |
| Manufacturer designation | NTN 23988 |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.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 | 160 mm |
| Largest outer diameter in 23900-series | 1820 mm |
| Width range across 23900-series | 45–315 mm |
| Bore position in 23900-series (smallest first) | 17 of 38 |
| Bore above smallest 23900-series size | 280 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 23988K | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 23900-series envelope, cage and ratings; this is the cylindrical-bore execution of the tapered-bore 23988K (K/K30 sleeve or tapered-seat mounting). Verify shaft arrangement. |
| 23988 | SKF | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 23988-CCK-W33 | SKF | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
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-NTN model number is decoded
The NTN order number 23988 identifies a 440×600×118 mm (17.323 × 23.622 × 4.646 in) spherical roller bearing, cylindrical bore, to the ISO 15 boundary plan. The leading digits are the ISO 15 dimension series (23900 series); the bore code resolves to 440 mm (two-digit code ×5, with the 00–03 exception table), and 600 mm OD / 118 mm width follow the general plan. Pu 325 kN is the catalogue fatigue load limit for 23988, used in the adjusted-life equation at contaminated or partial-film conditions typical of mining and vibrating duty. Equivalent-load planning keeps a radial plus moderate axial combination on 23988; if the axial component dominates, pair with a thrust bearing rather than running one roller row unloaded. Fillet radii on shaft and housing must clear the ring chamfers of the 118 mm-wide set; use the NTN shoulder/withdrawal-groove table rather than copying a ball-bearing layout.
Typical equipment & failure modes
Common applications
- large wind-turbine main-shaft arrangements
- steel-mill and heavy crusher main shafts
- mining shovel and dragline swing shafts
- cement-rotary-kiln support and trunnion rolls
Known failure patterns
- raceway spalling at the roller ends when misalignment or deflection concentrates the line contact
- pressed EA cage fatigue under sustained vibration when minimum load is not maintained
- roller-end smearing during skidding starts under light load and high viscosity grease
- water-induced pitting in washdown or outdoor duty without effective external seals
- brinelling from static overload or a hammer blow during sleeve mounting
Selection pitfalls — read before you substitute
- At 440 mm bore 23988 is normally mounted on adapter/withdrawal sleeves with hydraulic assistance; follow the NTN drive-up angle or oil-injection procedure — manual nut tightening cannot set the multi-tonne seating correctly.
- Do not confuse EA and EM at the same number: 23988 carries basic; swapping to the other cage execution changes mass, speed behaviour and sometimes suitability for vibration, even though the 440×600 mm envelope is identical.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 118 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- Do not confuse EA and EM at the same number: 23988 carries basic; swapping to the other cage execution changes mass, speed behaviour and sometimes suitability for vibration, even though the 440×600 mm envelope is identical.
- The D1/W33 groove only helps if the housing has a matching grease passage; mounting a grooved 23988 in a solid block with no port wastes the feature and leaves the centre rows under-lubricated.
- The 2260/4700 kN ratings, 325 kN Pu and 101000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 23988 (basic); another maker's same-envelope part revises internal geometry, so re-verify ratings and cage before substitution on vibrating or rated drives.
Frequently asked questions
What are the dimensions and catalogue data of 23988?
23988 is an NTN double-row spherical roller bearing to ISO 15: 440 mm bore, 600 mm OD and 118 mm width (17.323 × 23.622 × 4.646 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 2260 kN, C0 4700 kN, Pu 325 kN, grease limiting speed 500 r/min, oil 650 r/min, mass about 101000 g. It is open, with pressed-steel cage (standard execution).
What is the difference between the K/K30 tapered bore and the cylindrical bore versions?
23988 has a cylindrical bore and mounts directly on a machined shaft seat. Its tapered-bore counterpart is 23988K (K = 1:12, or K30 = 1:30 on the wide series), intended for adapter/withdrawal-sleeve mounting.
What do EA and EM mean on NTN spherical roller bearings?
EA is the NTN standard-capacity/high-capacity execution with a pressed sheet-steel window cage; EM is the high-capacity execution with a one-piece machined brass cage. Both use the optimised symmetric-roller design, but cage identity changes mass, speed behaviour and suitability for duties like vibrating screens, so they are separate order numbers. 23988 is the basic execution.
What do D1 and W33 mean on 23988?
23988 is listed without a D1/W33 outer-ring groove in 2203E; lubrication is supplied from the ring sides. D1 (NTN spelling) and W33 add the annular groove plus holes and are ordered as distinct suffixed executions of the same envelope.
How much misalignment and axial load can 23988 take?
The sphered outer raceway compensates static and dynamic misalignment in the order of 1–2° (verify the exact 2203E figure for the 23900 series); beyond that, load concentrates on one roller row. Load is predominantly radial with a moderate axial share in either direction — 2260 kN C / 4700 kN C0 — but sustained pure axial load is not recommended because it unloads one row.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.