NJ2308-ECP bearing: complete specifications & equivalents
The NJ2308-ECP is a ISO 15 radial bearing sized 40 x 90 x 33 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 40 mm |
| Outer diameter D | 90 mm |
| Width B | 33 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 129 kN |
| Basic static load rating C0 | 120 kN |
| Fatigue load limit Pu | 15.3 kN |
| Reference speed (thermal) | 8000 rpm |
| Limiting speed (mechanical) | 9500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 950 g |
| Manufacturer designation | SKF NJ 2308 ECP |
| 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 & NJ2300-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 3.543 in |
| Width B | 1.299 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 25 mm |
| Smallest bore in NJ2300-series | 20 mm |
| Largest outer diameter in NJ2300-series | 540 mm |
| Width range across NJ2300-series | 21–165 mm |
| Bore position in NJ2300-series (smallest first) | 5 of 28 |
| Bore above smallest NJ2300-series size | 20 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NUP2308-ECP | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 40×90×33 mm and equivalent catalogue ratings; the NUP execution differs in flange/retaining-ring configuration — boundary-dimension interchangeable, but axial-locating behaviour is not identical. |
| NU2308 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 40×90×33 mm and equivalent catalogue ratings; the NU execution differs in flange/retaining-ring configuration — boundary-dimension interchangeable, but axial-locating behaviour is not identical. |
| NU2308 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 40×90×33 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 NJ2308-ECP model number is decoded
In SKF catalogue PUB BU/P1 17000, SKF NJ 2308 ECP denotes a single-row caged cylindrical roller bearing on the ISO 15 40×90×33 mm envelope, dimension series 23 (medium-section, wide), with catalogue mass 950 g. The NJ configuration means two integral flanges on the inner ring and no flanges on the outer ring; the inner ring retains the roller set; functionally the bearing is able to locate the shaft axially in one direction; an HJ angle ring on the opposite side converts it into two-direction location. The ECP suffix marks the E-design execution with a glass-fibre reinforced polyamide (PA66) cage, limited to 120 °C continuous. Speed planning for NJ2308-ECP: the catalogue lists 8,000 r/min thermal reference speed and 9,500 r/min mechanical limiting speed. The mass entry 950 g covers the complete catalogue execution. 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 40 mm seat normally takes a k5 interference with an H7 housing bore when the inner ring rotates.
Typical equipment & failure modes
Common applications
- machine-tool radial spindle supports
- conveyor drive-pulley shafts
- medium industrial gearbox shafts
- electric-motor shafts in pumps and fans
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
- polymer cage softening above 120 °C
- 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 NJ bearing where two-direction axial location is required without an HJ angle ring
- The dimension series 23 (medium-section, wide) envelope is shared with the N/NU/NJ/NUP executions of 2308, but flange configuration and axial-locating behaviour differ — quote the full SKF NJ 2308 ECP 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 90 mm raceway.
- Press-fit force goes through ring faces only; driving a ring home through the rollers brinells the 90 mm raceway.
- The 129/120 kN ratings are SKF catalogue 17000 (2018) values for the ECP 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 NJ2308-ECP?
SKF NJ 2308 ECP is a single-row caged cylindrical roller bearing with 40 mm bore, 90 mm OD and 33 mm width per ISO 15. SKF lists C 129 kN, C0 120 kN, Pu 15.3 kN, reference speed 8,000 r/min and limiting speed 9,500 r/min, mass about 950 g.
What does the NJ designation and ECP suffix mean?
The ECP suffix marks the E-design execution with a glass-fibre reinforced polyamide (PA66) cage, limited to 120 °C continuous. 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 NJ2308-ECP 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 NJ2308-ECP 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.