239-670K bearing: complete specifications & equivalents
The 239-670K is a ISO 15 radial bearing sized 670 x 900 x 170 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 670 mm |
| Outer diameter D | 900 mm |
| Width B | 170 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel |
| Basic dynamic load rating C | 4550 kN |
| Basic static load rating C0 | 10300 kN |
| Fatigue load limit Pu | 795 kN |
| Limiting speed (mechanical) | 300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 307000 g |
| Manufacturer designation | NTN 239/670K |
| 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 | 26.378 in |
|---|---|
| Outer diameter D | 35.433 in |
| Width B | 6.693 in |
| ISO bore code | 39 |
| Radial section height (D−d)/2 | 115 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) | 25 of 38 |
| Bore above smallest 23900-series size | 510 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 239-670 | 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 239-670 — 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 239-670K model number is decoded
239/670K belongs to the 23900 series of NTN spherical rollers: self-aligning, high radial capacity, moderate axial load in either direction. On the NTN nameplate the suffix cluster after the size reads in order: cage design (—), bore (K), lubrication feature (none); 239/670K is assembled exactly in that order. The 115.0 mm radial section over the 670 mm bore carries two roller rows; capacity per millimetre of bore is about 6.8 kN/mm, among the highest of rolling bearings for the ISO 15 envelope. Pu 795 kN against C0 10300 kN anchors the contamination derating; for dirty mining duty the adjusted life of 239/670K moves with cleanliness far more than with small C variations. Mount 239/670K on its adapter or withdrawal sleeve on the 670 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
- machined EM cage wear from inadequate oil film at the cage-guiding surfaces
- sliding wear and heat when relubrication intervals ignore the groove (D1/W33) supply path
- 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 670 mm bore 239/670K 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: 239/670K carries basic; swapping to the other cage execution changes mass, speed behaviour and sometimes suitability for vibration, even though the 670×900 mm envelope is identical.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 170 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 300 r/min grease rating is lost to abrasive wear long before fatigue.
- The 1:12 tapered bore is the only difference from the cylindrical-bore 239/670: envelopes and ratings match, but drive-up tooling, sleeve and seat do not — never mix the two mounting methods.
- The 4550/10300 kN ratings, 795 kN Pu and 307000 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 239/670K (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 239/670K?
239/670K is an NTN double-row spherical roller bearing to ISO 15: 670 mm bore, 900 mm OD and 170 mm width (26.378 × 35.433 × 6.693 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 4550 kN, C0 10300 kN, Pu 795 kN, grease limiting speed 300 r/min, oil 390 r/min, mass about 307000 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. 239/670K 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 239/670.
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. 239/670K is the basic execution.
What do D1 and W33 mean on 239/670K?
239/670K 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 239/670K 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 — 4550 kN C / 10300 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.