240-750B bearing: complete specifications & equivalents
The 240-750B 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 | 1060000 g |
| Manufacturer designation | NTN 240/750B |
| 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 |
|---|---|---|---|
| 240-750BK30 | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 24000-series envelope, cage and ratings; this is the cylindrical-bore execution of the tapered-bore 240-750BK30 (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 240-750B model number is decoded
240/750B is the basic execution of NTN's spherical roller range for a 750 mm shaft — 11300 kN basic dynamic capacity in a 1060000 g, open ISO 15 envelope. Digit by digit the code reads as spherical-roller dimension series plus 750 mm bore; the 335 mm width is the wide ISO 15 section, which is why spherical rollers interchange dimensionally but not in cage or rating detail. NTN prints two speeds for 240/750B: 220 r/min grease and 280 r/min oil — the gap of 60 r/min reflects oil cooling of the heavy roller set. Grease/oil ratio: the 220 r/min limiting value is .79 of the 280 r/min oil value; heavy 335 mm-wide cages run hot in churning grease, so quantity and groove supply both matter. Supply grease through the outer-ring feature during commissioning and at the calculated interval, rotating the 750 mm bore assembly by hand to distribute it across both rows.
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
- pressed EA cage fatigue under sustained vibration when minimum load is not maintained
- micro-pitting when the EHL film is thinner than the raceway composite roughness
- asymmetric wear on the two roller rows from sustained angular misalignment beyond the self-aligning range
- false brinelling on stopped machines exposed to screen or crusher vibration
Selection pitfalls — read before you substitute
- At 750 mm bore 240/750B 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 335 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- 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.
- 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.
- 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 1060000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 240/750B (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 240/750B?
240/750B 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 1060000 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?
240/750B has a cylindrical bore and mounts directly on a machined shaft seat. Its tapered-bore counterpart is 240/750BK30 (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. 240/750B is the basic execution.
What do D1 and W33 mean on 240/750B?
240/750B 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 240/750B 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.