NJ2988-ECML bearing: complete specifications & equivalents
The NJ2988-ECML is a ISO 15 radial bearing sized 440 x 600 x 95 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 440 mm |
| Outer diameter D | 600 mm |
| Width B | 95 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 1870 kN |
| Basic static load rating C0 | 3900 kN |
| Fatigue load limit Pu | 340 kN |
| Reference speed (thermal) | 1100 rpm |
| Limiting speed (mechanical) | 1600 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 83000 g |
| Manufacturer designation | SKF NJ 2988 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 & NJ2900-series range
| Bore d | 17.323 in |
|---|---|
| Outer diameter D | 23.622 in |
| Width B | 3.74 in |
| ISO bore code | 88 |
| Radial section height (D−d)/2 | 80 mm |
| Smallest bore in NJ2900-series | 340 mm |
| Largest outer diameter in NJ2900-series | 850 mm |
| Width range across NJ2900-series | 72–128 mm |
| Bore position in NJ2900-series (smallest first) | 3 of 5 |
| Bore above smallest NJ2900-series size | 100 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NU2988-ECML | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 440×600×95 mm and equivalent catalogue ratings; the NU 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 NJ2988-ECML model number is decoded
For a 440 mm shaft, SKF lists NJ2988-ECML as single-row caged cylindrical roller: 600 mm OD, 95 mm wide, Pu 340 kN, the catalogue lists 1,100 r/min thermal reference speed and 1,600 r/min mechanical limiting speed. Reading the NJ prefix: two integral flanges on the inner ring and no flanges on the outer ring; the inner ring retains the roller set. This makes the execution able to locate the shaft axially in one direction; an HJ angle ring on the opposite side converts it into two-direction location. The ECML suffix denotes the E-design execution with a one-piece machined brass cage for higher-temperature and higher-speed continuous duty. Load-per-bore for the 440 mm seat is about 4.25 kN/mm, typical of dimension series 29 (compact OD, normal width); use C0 3900 kN for static checks such as crane hook blocks standing under load. Mounting: orient the inner-ring flange side toward the axial load direction; if an HJ angle ring is used, verify its fit and clearance before locking the arrangement. A 440 mm seat normally takes a m6 interference with an H6 housing bore when the inner ring rotates.
Typical equipment & failure modes
Common applications
- offshore drawworks shafts
- large rolling-mill drive trains
- marine propulsion line shafts
- heavy turbogenerator rotor supports
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
- roller-end scoring from inadequate oil flow in the roller-raceway contact
- 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 NJ bearing where two-direction axial location is required without an HJ angle ring
- The dimension series 29 (compact OD, normal width) envelope is shared with the N/NU/NJ/NUP executions of 2988, but flange configuration and axial-locating behaviour differ — quote the full SKF NJ 2988 ECML and do not substitute rib styles without checking the shaft locating scheme.
- Shaft and housing fillets must clear the bearing chamfers; an oversized radius tilts the 95 mm-wide ring and concentrates load.
- Press-fit force goes through ring faces only; driving a ring home through the rollers brinells the 600 mm raceway.
- The 1870/3900 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 NJ2988-ECML?
SKF NJ 2988 ECML is a single-row caged cylindrical roller bearing with 440 mm bore, 600 mm OD and 95 mm width per ISO 15. SKF lists C 1870 kN, C0 3900 kN, Pu 340 kN, reference speed 1,100 r/min and limiting speed 1,600 r/min, mass about 83000 g.
What does the NJ 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 inner ring and no flanges on the outer ring; the inner ring retains the roller set.
Can NJ2988-ECML take axial load and locate the shaft?
In one direction only, via the two inner-ring flanges. Add an HJ angle ring on the opposite side for two-direction location.
How does NJ2988-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.