NU340-ECML bearing: complete specifications & equivalents
The NU340-ECML is a ISO 15 radial bearing sized 200 x 420 x 80 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 200 mm |
| Outer diameter D | 420 mm |
| Width B | 80 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 1230 kN |
| Basic static load rating C0 | 1630 kN |
| Fatigue load limit Pu | 150 kN |
| Reference speed (thermal) | 1400 rpm |
| Limiting speed (mechanical) | 2800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 57000 g |
| Manufacturer designation | SKF NU 340 ECML |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings |
| Last verified | 2026-09-26 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings) · extracted 2026-09-26
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.com.
Dimensions in inches & NU300-series range
| Bore d | 7.874 in |
|---|---|
| Outer diameter D | 16.535 in |
| Width B | 3.15 in |
| ISO bore code | 40 |
| Radial section height (D−d)/2 | 110 mm |
| Smallest bore in NU300-series | 17 mm |
| Largest outer diameter in NU300-series | 620 mm |
| Width range across NU300-series | 14–109 mm |
| Bore position in NU300-series (smallest first) | 29 of 33 |
| Bore above smallest NU300-series size | 183 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ340-ECML | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 200×420×80 mm and equivalent catalogue ratings; the NJ execution differs in flange/retaining-ring configuration — boundary-dimension interchangeable, but axial-locating behaviour is not identical. |
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 NU340-ECML model number is decoded
SKF NU 340 ECML is a single-row caged cylindrical roller bearing sized 200×420×80 mm — a dimension series 3 (medium-section ISO 15 envelope), listed in SKF catalogue PUB BU/P1 17000 ch. 6.1. The NU configuration means two integral flanges on the outer ring and no flanges on the inner ring, so the inner ring together with the roller set is separable; functionally the bearing is non-locating: the inner ring assembly can float axially in both directions and the bearing cannot support axial load. The ECML suffix denotes the E-design execution with a one-piece machined brass cage for higher-temperature and higher-speed continuous duty. The one-piece machined brass cage is reflected in the published speeds and temperature limits. Speed planning for NU340-ECML: the catalogue lists 1,400 r/min thermal reference speed and 2,800 r/min mechanical limiting speed. The mass entry 57000 g covers the complete catalogue execution. Assembly note: fit the inner ring and roller assembly onto the shaft and the outer ring into the housing independently; thermal expansion is absorbed by axial float, so do not trap the inner ring between shaft shoulders. Heat steel rings inductively to max 120 °C.
Typical equipment & failure modes
Common applications
- mining hoist and winder shafts
- offshore drawworks shafts
- large rolling-mill drive trains
- marine propulsion line shafts
Known failure patterns
- inner-ring raceway spalling from overload or contamination in the line-contact hertz zone
- outer-ring raceway fatigue after extended service at loads above the catalogue L10 rating
- cage pocket wear from roller skew at light load
- cage pocket wear from roller skidding at insufficient radial load or during start-up before oil film build-up
- surface distress (micro-pitting) when the EHL film falls below the composite roughness at high specific load
- edge-loading fatigue after shaft deflection beyond the 3–4 minute alignment limit
- fretting corrosion on a loose rotating shaft seat or in a vibratory stand-still
Selection pitfalls — read before you substitute
- Do not use a NU bearing where axial load must be carried — the design carries radial load only
- The dimension series 3 (medium-section ISO 15 envelope) envelope is shared with the N/NU/NJ/NUP executions of 340, but flange configuration and axial-locating behaviour differ — quote the full SKF NU 340 ECML and do not substitute rib styles without checking the shaft locating scheme.
- Press-fit force goes through ring faces only; driving a ring home through the rollers brinells the 420 mm raceway.
- Press-fit force goes through ring faces only; driving a ring home through the rollers brinells the 420 mm raceway.
- The 1230/1630 kN ratings are SKF catalogue 17000 (2018) values for the ECML execution; re-verify against the current catalogue for critical drives and keep the catalogue version with the specification.
Frequently asked questions
What are the dimensions and catalogue data of NU340-ECML?
SKF NU 340 ECML is a single-row caged cylindrical roller bearing with 200 mm bore, 420 mm OD and 80 mm width per ISO 15. SKF lists C 1230 kN, C0 1630 kN, Pu 150 kN, reference speed 1,400 r/min and limiting speed 2,800 r/min, mass about 57000 g.
What does the NU designation and ECML suffix mean?
The ECML suffix denotes the E-design execution with a one-piece machined brass cage for higher-temperature and higher-speed continuous duty. Structurally this execution has two integral flanges on the outer ring and no flanges on the inner ring, so the inner ring together with the roller set is separable.
Can NU340-ECML take axial load and locate the shaft?
No — the inner ring has no flanges, so the NU bearing is non-locating and carries radial load only; use NJ (one direction), NUP (both directions) or a paired thrust bearing for axial duty.
How does NU340-ECML compare with the other executions in the same envelope?
The N/NU/NJ/NUP executions share the ISO 15 envelope and load ratings but differ in flange arrangement and axial-locating behaviour; quote the exact order number.
What limits the service life of this bearing most often?
Line-contact fatigue above the L10 rating, cage wear at light loads and high temperatures, and edge loading from misalignment beyond about 3–4 minutes of arc are the typical failure drivers.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018), ch. 6.1 single-row cylindrical roller bearings on 2026-09-26. Read our editorial & correction policy.