230-850B bearing: complete specifications & equivalents
The 230-850B 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 | 1050000 g |
| Manufacturer designation | NTN 230/850B |
| 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 |
|---|---|---|---|
| 230-850BK | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 23000-series envelope, cage and ratings; this is the cylindrical-bore execution of the tapered-bore 230-850BK (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 230-850B model number is decoded
230/850B is an NTN double-row spherical roller bearing: two rows of symmetric rollers on a sphered outer raceway, 850×1220×272 mm to ISO 15, with pressed-steel cage (standard execution). On the NTN nameplate the suffix cluster after the size reads in order: cage design (—), bore (cylindrical), lubrication feature (none); 230/850B is assembled exactly in that order. NTN prints two speeds for 230/850B: 210 r/min grease and 270 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 230/850B; if the axial component dominates, pair with a thrust bearing rather than running one roller row unloaded. Supply grease through the outer-ring feature during commissioning and at the calculated interval, rotating the 850 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
- 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
- hard-particle indentation through the open arrangement in dusty mining duty
- brinelling from static overload or a hammer blow during sleeve mounting
Selection pitfalls — read before you substitute
- At 850 mm bore 230/850B 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.
- 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 850 mm bearing, and drive-up procedures differ.
- Minimum load must be maintained even at rest under vibration: an unloaded 230/850B on a stopped screen false-brinells; parking brakes and shaker isolation both matter.
- 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 850 mm bearing, and drive-up procedures differ.
- Oil relubrication toward 270 r/min needs drain and level design; flooding the 272 mm cavity churns heat through the heavy roller set and cage despite the higher oil speed figure.
- The 10900/22700 kN ratings, 1510 kN Pu and 1050000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 230/850B (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 230/850B?
230/850B 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 1050000 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?
230/850B has a cylindrical bore and mounts directly on a machined shaft seat. Its tapered-bore counterpart is 230/850BK (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. 230/850B is the basic execution.
What do D1 and W33 mean on 230/850B?
230/850B 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 230/850B 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.