NU3980-ECMA bearing: complete specifications & equivalents
The NU3980-ECMA is a ISO 15 radial bearing sized 400 x 540 x 106 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 400 mm |
| Outer diameter D | 540 mm |
| Width B | 106 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 1760 kN |
| Basic static load rating C0 | 3750 kN |
| Fatigue load limit Pu | 320 kN |
| Reference speed (thermal) | 1000 rpm |
| Limiting speed (mechanical) | 1500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 74500 g |
| Manufacturer designation | SKF NU 3980 ECMA |
| 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 & NU3900-series range
| Bore d | 15.748 in |
|---|---|
| Outer diameter D | 21.26 in |
| Width B | 4.173 in |
| ISO bore code | 80 |
| Radial section height (D−d)/2 | 70 mm |
| Smallest bore in NU3900-series | 400 mm |
| Largest outer diameter in NU3900-series | 540 mm |
| Width range across NU3900-series | 106–106 mm |
| Bore position in NU3900-series (smallest first) | 1 of 1 |
| Bore above smallest NU3900-series size | 0 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the NU3980-ECMA model number is decoded
NU3980-ECMA is the 400 mm bore entry in the NU3900 range: a 400×540×106 mm single-row caged cylindrical roller bearing with a one-piece machined brass cage, rated C 1760 kN / C0 3750 kN. 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 ECMA 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 NU3980-ECMA: the catalogue lists 1,000 r/min thermal reference speed and 1,500 r/min mechanical limiting speed. The mass entry 74500 g covers the complete catalogue execution. Mounting: 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. A 400 mm seat normally takes a m6 interference with an H6 housing bore when the inner ring rotates.
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
- hard-particle indentation of the raceway in unfiltered oil systems
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 39 (compact OD) envelope is shared with the N/NU/NJ/NUP executions of 3980, but flange configuration and axial-locating behaviour differ — quote the full SKF NU 3980 ECMA 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 540 mm raceway.
- Shaft and housing fillets must clear the bearing chamfers; an oversized radius tilts the 106 mm-wide ring and concentrates load.
- The 1760/3750 kN ratings are SKF catalogue 17000 (2018) values for the ECMA 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 NU3980-ECMA?
SKF NU 3980 ECMA is a single-row caged cylindrical roller bearing with 400 mm bore, 540 mm OD and 106 mm width per ISO 15. SKF lists C 1760 kN, C0 3750 kN, Pu 320 kN, reference speed 1,000 r/min and limiting speed 1,500 r/min, mass about 74500 g.
What does the NU designation and ECMA suffix mean?
The ECMA 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 NU3980-ECMA 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 NU3980-ECMA 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.