N221-ECP bearing: complete specifications & equivalents
The N221-ECP is a ISO 15 radial bearing sized 105 x 190 x 36 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 105 mm |
| Outer diameter D | 190 mm |
| Width B | 36 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 300 kN |
| Basic static load rating C0 | 315 kN |
| Fatigue load limit Pu | 36.5 kN |
| Reference speed (thermal) | 3800 rpm |
| Limiting speed (mechanical) | 4300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3900 g |
| Manufacturer designation | SKF N 221 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 & N200-series range
| Bore d | 4.134 in |
|---|---|
| Outer diameter D | 7.48 in |
| Width B | 1.417 in |
| ISO bore code | 21 |
| Radial section height (D−d)/2 | 42.5 mm |
| Smallest bore in N200-series | 17 mm |
| Largest outer diameter in N200-series | 230 mm |
| Width range across N200-series | 12–40 mm |
| Bore position in N200-series (smallest first) | 19 of 22 |
| Bore above smallest N200-series size | 88 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| NJ221-ECP | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 105×190×36 mm and equivalent catalogue ratings; the NJ execution differs in flange/retaining-ring configuration — boundary-dimension interchangeable, but axial-locating behaviour is not identical. |
| NU221-ECP | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 105×190×36 mm and equivalent catalogue ratings; the NU execution differs in flange/retaining-ring configuration — boundary-dimension interchangeable, but axial-locating behaviour is not identical. |
| NUP221-ECP | SKF | full Dimensions and internal design equivalent — standard interchange. | Same ISO 15 envelope 105×190×36 mm and equivalent catalogue ratings; the NUP 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 N221-ECP model number is decoded
SKF N 221 ECP is a single-row caged cylindrical roller bearing sized 105×190×36 mm — a dimension series 2 (light-section ISO 15 envelope), listed in SKF catalogue PUB BU/P1 17000 ch. 6.1. The N configuration means two integral flanges on the inner ring and no flanges on the outer ring, so the plain outer ring is the separable part; functionally the bearing is non-locating: the outer ring can displace axially in both directions and the bearing carries radial load only. Reading the order-string suffix ECP: the E-design execution with a glass-fibre reinforced polyamide (PA66) cage, limited to 120 °C continuous. Selection arithmetic: C0/C ≈ 1.05 (315 against 300 kN), and the Pu figure 36.5 kN is the fatigue load-limit floor for the SKF life equation; the catalogue lists 3,800 r/min thermal reference speed and 4,300 r/min mechanical limiting speed. Fit practice for N221-ECP: the outer ring slides in its housing seat; provide axial retention for the outer ring only if the application requires it, and let it float to absorb shaft expansion. Single-row cylindrical rollers tolerate only about 3–4 minutes of arc misalignment, so verify shaft and housing alignment.
Typical equipment & failure modes
Common applications
- heavy gearbox and pinion shafts
- large pump and blower rotors
- rolling-mill auxiliary drive shafts
- paper-machine press rolls
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
- false brinelling on standby machines exposed to external vibration
Selection pitfalls — read before you substitute
- Do not use a N bearing where axial load must be carried — the design carries radial load only
- The dimension series 2 (light-section ISO 15 envelope) envelope is shared with the N/NU/NJ/NUP executions of 221, but flange configuration and axial-locating behaviour differ — quote the full SKF N 221 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 190 mm raceway.
- Press-fit force goes through ring faces only; driving a ring home through the rollers brinells the 190 mm raceway.
- The 300/315 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 N221-ECP?
SKF N 221 ECP is a single-row caged cylindrical roller bearing with 105 mm bore, 190 mm OD and 36 mm width per ISO 15. SKF lists C 300 kN, C0 315 kN, Pu 36.5 kN, reference speed 3,800 r/min and limiting speed 4,300 r/min, mass about 3900 g.
What does the N 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, so the plain outer ring is the separable part.
Can N221-ECP take axial load and locate the shaft?
No — the plain outer ring has no flanges, so the N bearing floats axially and is for radial load; locate the shaft with a separate bearing.
How does N221-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.