230-750BK bearing: complete specifications & equivalents
The 230-750BK is a ISO 15 radial bearing sized 750 x 1090 x 250 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 | 250 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 9100 kN |
| Basic static load rating C0 | 18300 kN |
| Fatigue load limit Pu | 1290 kN |
| Limiting speed (mechanical) | 250 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 763000 g |
| Manufacturer designation | NTN 230/750BK |
| 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 & 23000-series range
| Bore d | 29.528 in |
|---|---|
| Outer diameter D | 42.913 in |
| Width B | 9.843 in |
| ISO bore code | 30 |
| Radial section height (D−d)/2 | 170 mm |
| Smallest bore in 23000-series | 70 mm |
| Largest outer diameter in 23000-series | 1580 mm |
| Width range across 23000-series | 27–345 mm |
| Bore position in 23000-series (smallest first) | 39 of 46 |
| Bore above smallest 23000-series size | 680 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 230-750B | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 23000-series envelope, cage and ratings; this is the tapered-bore execution (K, 1:12) of the cylindrical-bore 230-750B — 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 230-750BK model number is decoded
230/750BK is the basic execution of NTN's spherical roller range for a 750 mm shaft — 9100 kN basic dynamic capacity in a 763000 g, open ISO 15 envelope. The leading digits are the ISO 15 dimension series (23000 series); the bore code resolves to 750 mm (two-digit code ×5, with the 00–03 exception table), and 1090 mm OD / 250 mm width follow the general plan. NTN prints two speeds for 230/750BK: 250 r/min grease and 320 r/min oil — the gap of 70 r/min reflects oil cooling of the heavy roller set. With about 12.1 kN of C per millimetre of the 750 mm bore, 230/750BK screens interchange candidates quickly — then verify cage (EA/EM), bore (K/K30) and lubrication feature (D1/W33) suffixes. Mount 230/750BK on its adapter or withdrawal sleeve on the 750 mm plain shaft: oil the sleeve, fit the lock nut, drive up to the NTN-specified residual clearance (or use oil injection on large seats), then lock the tab washer.
Typical equipment & failure modes
Common applications
- heavy vibrating screens and grizzly feeders
- offshore and marine propulsion shaftlines
- large wind-turbine main-shaft arrangements
- steel-mill and heavy crusher main shafts
Known failure patterns
- lubricant starvation at the centre rib area when the D1/W33 groove is not connected to a relubrication supply
- 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
- rolling-contact fatigue after the catalogue L10 life at the actual load
- fretting corrosion between adapter sleeve and tapered bore when the drive-up is insufficient
Selection pitfalls — read before you substitute
- At 750 mm bore 230/750BK 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.
- The 1:12 tapered bore is the only difference from the cylindrical-bore 230/750B: envelopes and ratings match, but drive-up tooling, sleeve and seat do not — never mix the two mounting methods.
- K and K30 are different tapers — K is 1:12 and K30 is 1:30 on the wide series; an adapter sleeve for one will not mount the other 750 mm bearing, and drive-up procedures differ.
- The D1/W33 groove only helps if the housing has a matching grease passage; mounting a grooved 230/750BK in a solid block with no port wastes the feature and leaves the centre rows under-lubricated.
- Oil relubrication toward 320 r/min needs drain and level design; flooding the 250 mm cavity churns heat through the heavy roller set and cage despite the higher oil speed figure.
- The 9100/18300 kN ratings, 1290 kN Pu and 763000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 230/750BK (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 230/750BK?
230/750BK is an NTN double-row spherical roller bearing to ISO 15: 750 mm bore, 1090 mm OD and 250 mm width (29.528 × 42.913 × 9.843 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 9100 kN, C0 18300 kN, Pu 1290 kN, grease limiting speed 250 r/min, oil 320 r/min, mass about 763000 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. 230/750BK 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 230/750B.
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. 230/750BK is the basic execution.
What do D1 and W33 mean on 230/750BK?
230/750BK 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 230/750BK take?
The sphered outer raceway compensates static and dynamic misalignment in the order of 1–2° (verify the exact 2203E figure for the 23000 series); beyond that, load concentrates on one roller row. Load is predominantly radial with a moderate axial share in either direction — 9100 kN C / 18300 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.