230-850BK bearing: complete specifications & equivalents
The 230-850BK is a ISO 15 radial bearing sized 850 x 1220 x 272 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 850 mm |
| Outer diameter D | 1220 mm |
| Width B | 272 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 10900 kN |
| Basic static load rating C0 | 22700 kN |
| Fatigue load limit Pu | 1510 kN |
| Limiting speed (mechanical) | 210 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1010000 g |
| Manufacturer designation | NTN 230/850BK |
| 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 | 33.465 in |
|---|---|
| Outer diameter D | 48.031 in |
| Width B | 10.709 in |
| ISO bore code | 30 |
| Radial section height (D−d)/2 | 185 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) | 41 of 46 |
| Bore above smallest 23000-series size | 780 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 230-850B | 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 230-850B — 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 230-850BK model number is decoded
For heavy radial load with misalignment on a 850 mm shaft, NTN supplies 230/850BK: sphered outer raceway, two roller rows, pressed-steel cage (standard execution), oil speed 270 r/min. Digit by digit the code reads as spherical-roller dimension series plus 850 mm bore; the 272 mm width is the wide ISO 15 section, which is why spherical rollers interchange dimensionally but not in cage or rating detail. At 10900 kN C and 1010000 g mass the 23000 series part is built for shock and vibration; the 272 mm-wide ring needs square abutments to keep both rows equally loaded. Catalogue mass 1010000 g (1010.00 kg) for the 850×1220×272 mm execution includes the basic cage and both roller rows; shaft and housing shoulders must support that ring squarely. Mount 230/850BK on its adapter or withdrawal sleeve on the 850 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
- large wind-turbine main-shaft arrangements
- steel-mill and heavy crusher main shafts
- mining shovel and dragline swing shafts
- cement-rotary-kiln support and trunnion rolls
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
- hard-particle indentation through the open arrangement in dusty mining duty
- rolling-contact fatigue after the catalogue L10 life at the actual load
Selection pitfalls — read before you substitute
- At 850 mm bore 230/850BK 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.
- Never substitute 230/850BK by envelope alone: the 22700 kN C0 and 1510 kN Pu are specific to the NTN basic execution, and vibrating duty depends heavily on cage identity.
- Never substitute 230/850BK by envelope alone: the 22700 kN C0 and 1510 kN Pu are specific to the NTN basic execution, and vibrating duty depends heavily on cage identity.
- The 1:12 tapered bore is the only difference from the cylindrical-bore 230/850B: 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 210 r/min grease rating is lost to abrasive wear long before fatigue.
- The 10900/22700 kN ratings, 1510 kN Pu and 1010000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 230/850BK (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 230/850BK?
230/850BK is an NTN double-row spherical roller bearing to ISO 15: 850 mm bore, 1220 mm OD and 272 mm width (33.465 × 48.031 × 10.709 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 10900 kN, C0 22700 kN, Pu 1510 kN, grease limiting speed 210 r/min, oil 270 r/min, mass about 1010000 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. 230/850BK 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 230/850B.
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. 230/850BK is the basic execution.
What do D1 and W33 mean on 230/850BK?
230/850BK 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 230/850BK 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 — 10900 kN C / 22700 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.