23268BK bearing: complete specifications & equivalents
The 23268BK 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 | 291000 g |
| Manufacturer designation | NTN 23268BK |
| 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 |
|---|---|---|---|
| 23268B | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 23200-series envelope, cage and ratings; this is the tapered-bore execution (K, 1:12) of the cylindrical-bore 23268B — mounting (adapter/withdrawal sleeve or tapered seat, drive-up) differs. 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 23268BK model number is decoded
23268BK belongs to the 23200 series of NTN spherical rollers: self-aligning, high radial capacity, moderate axial load in either direction. Digit by digit the code reads as spherical-roller dimension series plus 340 mm bore; the 224 mm width is the wide ISO 15 section, which is why spherical rollers interchange dimensionally but not in cage or rating detail. The 1:12 tapered bore mounts on an adapter/withdrawal sleeve (or tapered seat); drive-up sets the residual radial clearance and fixes the axial position of the 340 mm bore assembly. 340 mm bore is 13.386 in and 620 mm OD is 24.409 in; the ISO 15 envelope swaps between brands, but the 4950/8000 kN ratings and cage design are NTN 2203E values. After mounting on a tapered seat, lock the nut and re-check clearance after a short running-in period, because sleeve seating and ring lift-off can change the residual clearance of the 340 mm set.
Typical equipment & failure modes
Common applications
- large SAG/ball-mill trunnion and pinion shafts
- heavy vibrating screens and grizzly feeders
- offshore and marine propulsion shaftlines
- large wind-turbine main-shaft arrangements
Known failure patterns
- raceway spalling at the roller ends when misalignment or deflection concentrates the line contact
- cage damage when a mounting force is applied through the roller set instead of the ring face
- 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
- hard-particle indentation through the open arrangement in dusty mining duty
Selection pitfalls — read before you substitute
- At 340 mm bore 23268BK 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 1:12 tapered bore is the only difference from the cylindrical-bore 23268B: envelopes and ratings match, but drive-up tooling, sleeve and seat do not — never mix the two mounting methods.
- Open spherical rollers swallow dust in mining duty; specify labyrinth or taconite seals externally, or the 490 r/min grease rating is lost to abrasive wear long before fatigue.
- Oil relubrication toward 630 r/min needs drain and level design; flooding the 224 mm cavity churns heat through the heavy roller set and cage despite the higher oil speed figure.
- Do not confuse EA and EM at the same number: 23268BK carries basic; swapping to the other cage execution changes mass, speed behaviour and sometimes suitability for vibration, even though the 340×620 mm envelope is identical.
- The 4950/8000 kN ratings, 585 kN Pu and 291000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 23268BK (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 23268BK?
23268BK 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 291000 g. It is open, with pressed-steel cage (standard execution) and a 1:12 tapered bore.
What is the difference between the K/K30 tapered bore and the cylindrical bore versions?
K denotes a 1:12 tapered bore. 23268BK mounts on an adapter sleeve (or tapered shaft seat) and is driven up to the specified residual clearance; its cylindrical-bore counterpart in the same envelope and ratings is 23268B.
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. 23268BK is the basic execution.
What do D1 and W33 mean on 23268BK?
23268BK 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 23268BK 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.