23268B bearing: complete specifications & equivalents
The 23268B is a ISO 15 radial bearing sized 340 x 620 x 224 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 340 mm |
| Outer diameter D | 620 mm |
| Width B | 224 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 4950 kN |
| Basic static load rating C0 | 8000 kN |
| Fatigue load limit Pu | 585 kN |
| Limiting speed (mechanical) | 490 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 300000 g |
| Manufacturer designation | NTN 23268B |
| 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 | 13.386 in |
|---|---|
| Outer diameter D | 24.409 in |
| Width B | 8.819 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 140 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) | 19 of 34 |
| Bore above smallest 23200-series size | 250 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 23268BK | 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 23268BK (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 23268B model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, 23268B denotes the 340 mm bore spherical roller bearing (4950 kN C / 8000 kN C0) in the 23200 series, the self-aligning choice for heavy combined load. Numbering ties 23268B to its envelope and execution: same-number EA versus EM or plain variants share the 340 mm bore but differ in cage and sometimes mass, so they are quoted as separate articles. The bearing accepts predominantly radial load with a moderate axial share, but is not a pure thrust bearing: sustained axial-only load skids the unloaded row and damages the basic cage. Selection: the C0/C ratio of 1.62 (8000/4950 kN) reflects the heavy static and shock proportioning of 23268B; size the equivalent load at the required L10 with shock factor for the application. Never mount 23268B by striking the outer ring through the roller set; drive through ring faces (or the adapter sleeve nut) and support the ring square to avoid brinelling the 620 mm race.
Typical equipment & failure modes
Common applications
- steel-mill and heavy crusher main shafts
- mining shovel and dragline swing shafts
- cement-rotary-kiln support and trunnion rolls
- large SAG/ball-mill trunnion and pinion shafts
Known failure patterns
- raceway spalling at the roller ends when misalignment or deflection concentrates the line contact
- machined EM cage wear from inadequate oil film at the cage-guiding surfaces
- roller-end smearing during skidding starts under light load and high viscosity grease
- asymmetric wear on the two roller rows from sustained angular misalignment beyond the self-aligning range
- water-induced pitting in washdown or outdoor duty without effective external seals
Selection pitfalls — read before you substitute
- At 340 mm bore 23268B 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.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 224 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- Never substitute 23268B by envelope alone: the 8000 kN C0 and 585 kN Pu are specific to the NTN basic execution, and vibrating duty depends heavily on cage identity.
- Adapter-sleeve mounting requires the correct sleeve series and locknut for the 340 mm shaft; a sleeve sized to bore alone ignores thread, width and the oil-injection option on large K30 seats.
- Never substitute 23268B by envelope alone: the 8000 kN C0 and 585 kN Pu are specific to the NTN basic execution, and vibrating duty depends heavily on cage identity.
- The 4950/8000 kN ratings, 585 kN Pu and 300000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 23268B (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 23268B?
23268B is an NTN double-row spherical roller bearing to ISO 15: 340 mm bore, 620 mm OD and 224 mm width (13.386 × 24.409 × 8.819 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 4950 kN, C0 8000 kN, Pu 585 kN, grease limiting speed 490 r/min, oil 630 r/min, mass about 300000 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?
23268B has a cylindrical bore and mounts directly on a machined shaft seat. Its tapered-bore counterpart is 23268BK (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. 23268B is the basic execution.
What do D1 and W33 mean on 23268B?
23268B 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 23268B 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 — 4950 kN C / 8000 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.