NUP2304-ECP bearing: complete specifications & equivalents
The NUP2304-ECP is a ISO 15 radial bearing sized 20 x 52 x 21 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 20 mm |
| Outer diameter D | 52 mm |
| Width B | 21 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 47.5 kN |
| Basic static load rating C0 | 38 kN |
| Fatigue load limit Pu | 4.8 kN |
| Reference speed (thermal) | 15000 rpm |
| Limiting speed (mechanical) | 18000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 220 g |
| Manufacturer designation | SKF NUP 2304 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 & NUP2300-series range
| Bore d | 0.787 in |
|---|---|
| Outer diameter D | 2.047 in |
| Width B | 0.827 in |
| ISO bore code | 04 |
| Radial section height (D−d)/2 | 16 mm |
| Smallest bore in NUP2300-series | 20 mm |
| Largest outer diameter in NUP2300-series | 300 mm |
| Width range across NUP2300-series | 21–102 mm |
| Bore position in NUP2300-series (smallest first) | 1 of 21 |
| Bore above smallest NUP2300-series size | 0 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ2304-ECP | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 20×52×21 mm and equivalent catalogue ratings; the NJ execution differs in flange/retaining-ring configuration — boundary-dimension interchangeable, but axial-locating behaviour is not identical. |
| NU2304-ECP | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 20×52×21 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 NUP2304-ECP model number is decoded
NUP2304-ECP is the 20 mm bore entry in the NUP2300 range: a 20×52×21 mm single-row caged cylindrical roller bearing with a glass-fibre reinforced polyamide (PA66) window-type cage, rated C 47.5 kN / C0 38 kN. Structurally, the NUP design has two integral flanges on the outer ring plus one integral flange and one loose flange ring on the inner ring. In arrangement terms it is a locating bearing that positions the shaft axially in both directions while keeping the cylindrical-roller radial capacity. Reading the order-string suffix ECP: the E-design execution with a glass-fibre reinforced polyamide (PA66) cage, limited to 120 °C continuous. With C 47.5 kN and C0 38 kN, size the bearing on the 20×52 mm ISO 15 envelope and check the 4.8 kN Pu against the equivalent-load floor; the catalogue lists 15,000 r/min thermal reference speed and 18,000 r/min mechanical limiting speed. Assembly note: the loose inner-ring flange must be fitted on the correct side and retained by the shaft abutment; never omit it during reassembly or the bearing loses its two-direction locating function. Heat steel rings inductively to max 120 °C — the PA66 cage sets the ceiling.
Typical equipment & failure modes
Common applications
- motor-cycle and small-engine transmissions
- appliance and fan armature shafts
- small pump rotor shafts
- small industrial electric-motor 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
- polymer cage softening above 120 °C
- polymer cage cracking or softening after sustained running above 120 °C or with incompatible lubricant
- 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 NUP bearing where a floating non-locating bearing is required — the loose inner flange makes it a locating bearing
- The dimension series 23 (medium-section, wide) envelope is shared with the N/NU/NJ/NUP executions of 2304, but flange configuration and axial-locating behaviour differ — quote the full SKF NUP 2304 ECP and do not substitute rib styles without checking the shaft locating scheme.
- Catalogue reference and limiting speeds are different criteria: observe the mechanical ceiling even when thermal calculations allow more.
- Shaft and housing fillets must clear the bearing chamfers; an oversized radius tilts the 21 mm-wide ring and concentrates load.
- The 47.5/38 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 NUP2304-ECP?
SKF NUP 2304 ECP is a single-row caged cylindrical roller bearing with 20 mm bore, 52 mm OD and 21 mm width per ISO 15. SKF lists C 47.5 kN, C0 38 kN, Pu 4.8 kN, reference speed 15,000 r/min and limiting speed 18,000 r/min, mass about 220 g.
What does the NUP 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 outer ring plus one integral flange and one loose flange ring on the inner ring.
Can NUP2304-ECP take axial load and locate the shaft?
Yes, in both directions: the integral inner flange plus the loose flange ring close both axial paths. Do not pair it with another locating bearing without thermal clearance.
How does NUP2304-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.