232-750BK bearing: complete specifications & equivalents
The 232-750BK is a ISO 15 radial bearing sized 750 x 1360 x 475 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 | 1360 mm |
| Width B | 475 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 20300 kN |
| Basic static load rating C0 | 36500 kN |
| Fatigue load limit Pu | 1980 kN |
| Limiting speed (mechanical) | 180 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2960000 g |
| Manufacturer designation | NTN 232/750BK |
| 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 | 29.528 in |
|---|---|
| Outer diameter D | 53.543 in |
| Width B | 18.701 in |
| ISO bore code | 32 |
| Radial section height (D−d)/2 | 305 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) | 34 of 34 |
| Bore above smallest 23200-series size | 660 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 232-750B | 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 232-750B — 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 232-750BK model number is decoded
The NTN order number 232/750BK identifies a 750×1360×475 mm (29.528 × 53.543 × 18.701 in) spherical roller bearing, 1:12 tapered bore (K), to the ISO 15 boundary plan. Numbering ties 232/750BK 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 232/750BK: 180 r/min grease and 240 r/min oil — the gap of 60 r/min reflects oil cooling of the heavy roller set. Equivalent-load planning keeps a radial plus moderate axial combination on 232/750BK; if the axial component dominates, pair with a thrust bearing rather than running one roller row unloaded. 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 750 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
- lubricant starvation at the centre rib area when the D1/W33 groove is not connected to a relubrication supply
- 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
- false brinelling on stopped machines exposed to screen or crusher vibration
- false brinelling on stopped machines exposed to screen or crusher vibration
Selection pitfalls — read before you substitute
- At 750 mm bore 232/750BK 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.
- Do not confuse EA and EM at the same number: 232/750BK carries basic; swapping to the other cage execution changes mass, speed behaviour and sometimes suitability for vibration, even though the 750×1360 mm envelope is identical.
- Open spherical rollers swallow dust in mining duty; specify labyrinth or taconite seals externally, or the 180 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 180 r/min grease rating is lost to abrasive wear long before fatigue.
- Oil relubrication toward 240 r/min needs drain and level design; flooding the 475 mm cavity churns heat through the heavy roller set and cage despite the higher oil speed figure.
- The 20300/36500 kN ratings, 1980 kN Pu and 2960000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 232/750BK (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 232/750BK?
232/750BK is an NTN double-row spherical roller bearing to ISO 15: 750 mm bore, 1360 mm OD and 475 mm width (29.528 × 53.543 × 18.701 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 20300 kN, C0 36500 kN, Pu 1980 kN, grease limiting speed 180 r/min, oil 240 r/min, mass about 2960000 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. 232/750BK 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 232/750B.
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. 232/750BK is the basic execution.
What do D1 and W33 mean on 232/750BK?
232/750BK 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 232/750BK 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 — 20300 kN C / 36500 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.