23280B bearing: complete specifications & equivalents
The 23280B is a ISO 15 radial bearing sized 400 x 720 x 256 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 400 mm |
| Outer diameter D | 720 mm |
| Width B | 256 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 6500 kN |
| Basic static load rating C0 | 10600 kN |
| Fatigue load limit Pu | 740 kN |
| Limiting speed (mechanical) | 400 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 457000 g |
| Manufacturer designation | NTN 23280B |
| 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 & 23200-series range
| Bore d | 15.748 in |
|---|---|
| Outer diameter D | 28.346 in |
| Width B | 10.079 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 160 mm |
| Smallest bore in 23200-series | 90 mm |
| Largest outer diameter in 23200-series | 1360 mm |
| Width range across 23200-series | 52.4–475 mm |
| Bore position in 23200-series (smallest first) | 22 of 34 |
| Bore above smallest 23200-series size | 310 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 23280BK | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 23200-series envelope, cage and ratings; this is the cylindrical-bore execution of the tapered-bore 23280BK (K/K30 sleeve or tapered-seat mounting). Verify shaft arrangement. |
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 23280B model number is decoded
NTN lists 23280B with a cylindrical bore and plain outer ring (no D1/W33 groove): 400 mm bore, 720 mm OD, 256 mm width, rated 400 r/min on grease. Numbering ties 23280B to its envelope and execution: same-number EA versus EM or plain variants share the 400 mm bore but differ in cage and sometimes mass, so they are quoted as separate articles. Suffix reading on 23280B: the bare number is the standard open execution; B marks the standard large-bore internal design on slash-size 230–232 series; quote the full code because each suffix is a distinct article. Grease/oil ratio: the 400 r/min limiting value is .77 of the 520 r/min oil value; heavy 256 mm-wide cages run hot in churning grease, so quantity and groove supply both matter. On vibrating-duty shafts verify the radial clearance class and cage choice at order time; the open 23280B leaves sealing and the C3/C4 clearance decision to the application drawing.
Typical equipment & failure modes
Common applications
- cement-rotary-kiln support and trunnion rolls
- large SAG/ball-mill trunnion and pinion shafts
- heavy vibrating screens and grizzly feeders
- offshore and marine propulsion shaftlines
Known failure patterns
- lubricant starvation at the centre rib area when the D1/W33 groove is not connected to a relubrication supply
- machined EM cage wear from inadequate oil film at the cage-guiding surfaces
- micro-pitting when the EHL film is thinner than the raceway composite roughness
- hard-particle indentation through the open arrangement in dusty mining duty
- false brinelling on stopped machines exposed to screen or crusher vibration
Selection pitfalls — read before you substitute
- At 400 mm bore 23280B 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.
- K and K30 are different tapers — K is 1:12 and K30 is 1:30 on the wide series; an adapter sleeve for one will not mount the other 400 mm bearing, and drive-up procedures differ.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 256 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- Adapter-sleeve mounting requires the correct sleeve series and locknut for the 400 mm shaft; a sleeve sized to bore alone ignores thread, width and the oil-injection option on large K30 seats.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 256 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- The 6500/10600 kN ratings, 740 kN Pu and 457000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 23280B (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 23280B?
23280B is an NTN double-row spherical roller bearing to ISO 15: 400 mm bore, 720 mm OD and 256 mm width (15.748 × 28.346 × 10.079 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 6500 kN, C0 10600 kN, Pu 740 kN, grease limiting speed 400 r/min, oil 520 r/min, mass about 457000 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?
23280B has a cylindrical bore and mounts directly on a machined shaft seat. Its tapered-bore counterpart is 23280BK (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. 23280B is the basic execution.
What do D1 and W33 mean on 23280B?
23280B 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 23280B take?
The sphered outer raceway compensates static and dynamic misalignment in the order of 1–2° (verify the exact 2203E figure for the 23200 series); beyond that, load concentrates on one roller row. Load is predominantly radial with a moderate axial share in either direction — 6500 kN C / 10600 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.