240-750BK30 bearing: complete specifications & equivalents
The 240-750BK30 is a ISO 15 radial bearing sized 750 x 1090 x 335 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 750 mm |
| Outer diameter D | 1090 mm |
| Width B | 335 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 11300 kN |
| Basic static load rating C0 | 24600 kN |
| Fatigue load limit Pu | 1230 kN |
| Limiting speed (mechanical) | 220 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1040000 g |
| Manufacturer designation | NTN 240/750BK30 |
| 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 & 24000-series range
| Bore d | 29.528 in |
|---|---|
| Outer diameter D | 42.913 in |
| Width B | 13.189 in |
| ISO bore code | 40 |
| Radial section height (D−d)/2 | 170 mm |
| Smallest bore in 24000-series | 65 mm |
| Largest outer diameter in 24000-series | 1580 mm |
| Width range across 24000-series | 35–462 mm |
| Bore position in 24000-series (smallest first) | 35 of 42 |
| Bore above smallest 24000-series size | 685 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 240-750B | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 24000-series envelope, cage and ratings; this is the tapered-bore execution (K30, 1:30) of the cylindrical-bore 240-750B — 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 240-750BK30 model number is decoded
240/750BK30 is an NTN double-row spherical roller bearing: two rows of symmetric rollers on a sphered outer raceway, 750×1090×335 mm to ISO 15, with pressed-steel cage (standard execution). Numbering ties 240/750BK30 to its envelope and execution: same-number EA versus EM or plain variants share the 750 mm bore but differ in cage and sometimes mass, so they are quoted as separate articles. NTN prints two speeds for 240/750BK30: 220 r/min grease and 280 r/min oil — the gap of 60 r/min reflects oil cooling of the heavy roller set. Selection: the C0/C ratio of 2.18 (24600/11300 kN) reflects the heavy static and shock proportioning of 240/750BK30; size the equivalent load at the required L10 with shock factor for the application. Check the self-aligning movement after fitting: the housing should pivot freely around the sphered outer raceway; a pinched outer ring removes the alignment capacity the bearing was selected for.
Typical equipment & failure modes
Common applications
- offshore and marine propulsion shaftlines
- large wind-turbine main-shaft arrangements
- steel-mill and heavy crusher main shafts
- mining shovel and dragline swing shafts
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
- brinelling from static overload or a hammer blow during sleeve mounting
- water-induced pitting in washdown or outdoor duty without effective external seals
Selection pitfalls — read before you substitute
- At 750 mm bore 240/750BK30 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.
- Open spherical rollers swallow dust in mining duty; specify labyrinth or taconite seals externally, or the 220 r/min grease rating is lost to abrasive wear long before fatigue.
- The 1:30 tapered bore is the only difference from the cylindrical-bore 240/750B: envelopes and ratings match, but drive-up tooling, sleeve and seat do not — never mix the two mounting methods.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 335 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- Oil relubrication toward 280 r/min needs drain and level design; flooding the 335 mm cavity churns heat through the heavy roller set and cage despite the higher oil speed figure.
- The 11300/24600 kN ratings, 1230 kN Pu and 1040000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 240/750BK30 (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 240/750BK30?
240/750BK30 is an NTN double-row spherical roller bearing to ISO 15: 750 mm bore, 1090 mm OD and 335 mm width (29.528 × 42.913 × 13.189 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 11300 kN, C0 24600 kN, Pu 1230 kN, grease limiting speed 220 r/min, oil 280 r/min, mass about 1040000 g. It is open, with pressed-steel cage (standard execution) and a 1:30 tapered bore.
What is the difference between the K/K30 tapered bore and the cylindrical bore versions?
K30 denotes a 1:30 tapered bore (the wide 24000 series). 240/750BK30 mounts on a matching adapter or withdrawal sleeve on a plain 750 mm shaft and is driven up to a measured radial clearance; the cylindrical-bore counterpart is 240/750B.
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. 240/750BK30 is the basic execution.
What do D1 and W33 mean on 240/750BK30?
240/750BK30 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 240/750BK30 take?
The sphered outer raceway compensates static and dynamic misalignment in the order of 1–2° (verify the exact 2203E figure for the 24000 series); beyond that, load concentrates on one roller row. Load is predominantly radial with a moderate axial share in either direction — 11300 kN C / 24600 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.