239-950K bearing: complete specifications & equivalents
The 239-950K is a ISO 15 radial bearing sized 950 x 1250 x 224 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 950 mm |
| Outer diameter D | 1250 mm |
| Width B | 224 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 8650 kN |
| Basic static load rating C0 | 20500 kN |
| Fatigue load limit Pu | 1390 kN |
| Limiting speed (mechanical) | 190 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 749000 g |
| Manufacturer designation | NTN 239/950K |
| 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 & 23900-series range
| Bore d | 37.402 in |
|---|---|
| Outer diameter D | 49.213 in |
| Width B | 8.819 in |
| ISO bore code | 39 |
| Radial section height (D−d)/2 | 150 mm |
| Smallest bore in 23900-series | 160 mm |
| Largest outer diameter in 23900-series | 1820 mm |
| Width range across 23900-series | 45–315 mm |
| Bore position in 23900-series (smallest first) | 31 of 38 |
| Bore above smallest 23900-series size | 790 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 239-950 | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 23900-series envelope, cage and ratings; this is the tapered-bore execution (K, 1:12) of the cylindrical-bore 239-950 — 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 239-950K model number is decoded
In NTN Ball and Roller Bearings CAT.No.2203E, 239/950K denotes the 950 mm bore spherical roller bearing (8650 kN C / 20500 kN C0) in the 23900 series, the self-aligning choice for heavy combined load. Reading the full code: the number gives the 950×1250 mm envelope, — names the cage/capacity execution, K marks the 1:12 tapered bore for adapter/withdrawal-sleeve mounting, and plain outer ring (no D1/W33 groove) completes the order number. At 8650 kN C and 749000 g mass the 23900 series part is built for shock and vibration; the 224 mm-wide ring needs square abutments to keep both rows equally loaded. With about 9.1 kN of C per millimetre of the 950 mm bore, 239/950K screens interchange candidates quickly — then verify cage (EA/EM), bore (K/K30) and lubrication feature (D1/W33) suffixes. Check the self-aligning movement after fitting: the housing should pivot freely around the sphered outer raceway; a pinched outer ring removes the alignment capacity the bearing was selected for.
Typical equipment & failure modes
Common applications
- mining shovel and dragline swing shafts
- cement-rotary-kiln support and trunnion rolls
- large SAG/ball-mill trunnion and pinion shafts
- heavy vibrating screens and grizzly feeders
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
- false brinelling on stopped machines exposed to screen or crusher vibration
- asymmetric wear on the two roller rows from sustained angular misalignment beyond the self-aligning range
Selection pitfalls — read before you substitute
- At 950 mm bore 239/950K 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 239/950: envelopes and ratings match, but drive-up tooling, sleeve and seat do not — never mix the two mounting methods.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 224 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 224 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 190 r/min grease rating is lost to abrasive wear long before fatigue.
- The 8650/20500 kN ratings, 1390 kN Pu and 749000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 239/950K (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 239/950K?
239/950K is an NTN double-row spherical roller bearing to ISO 15: 950 mm bore, 1250 mm OD and 224 mm width (37.402 × 49.213 × 8.819 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 8650 kN, C0 20500 kN, Pu 1390 kN, grease limiting speed 190 r/min, oil 250 r/min, mass about 749000 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. 239/950K 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 239/950.
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. 239/950K is the basic execution.
What do D1 and W33 mean on 239/950K?
239/950K 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 239/950K take?
The sphered outer raceway compensates static and dynamic misalignment in the order of 1–2° (verify the exact 2203E figure for the 23900 series); beyond that, load concentrates on one roller row. Load is predominantly radial with a moderate axial share in either direction — 8650 kN C / 20500 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.