N304 Cylindrical Roller Bearing (20x52x15mm)
How to read this designation →
Bearing dimensions and basic technical information.
Manufacturer Ratings
Load-rating symbols are printed as each manufacturer writes them in its own catalogue, so the same quantity can carry a different symbol from brand to brand.
| Brand | Dynamic Load Rating | Static Load Rating | Fatigue Load Limit |
|---|---|---|---|
| SKF N 304 ECP | 35.5 kN | 26 kN | 3.25 kN |
| NSK N304 | 26.3 kN | 17.3 kN | — |
| Timken N304ETP | 32 kN | 27 kN | — |
Speed Ratings
Speed limits depend on sealing and lubrication, and definitions differ by manufacturer. Contact-sealed variants are normally greased for life and run slower. Always confirm the exact variant in the manufacturer's table.
| Brand | Grease open / shielded | Oil open | Reference | Limiting |
|---|---|---|---|---|
| SKF N 304 ECP | — | — | 15,000 r/min | 18,000 r/min |
| NSK N304 | 10,000 r/min | 12,000 r/min | 14,000 r/min | — |
| Timken N304ETP | 10,100 r/min | 12,100 r/min | — | — |
References
- SKF — SKF Group, Rolling Bearings, PUB BU/P1 17000/1 EN, Oct. 2018.
- NSK — NSK Ltd., Rolling Bearings for Industrial Machinery, CAT. No. E1103, Tokyo, Japan, Jan. 2025.
- Timken — The Timken Company, Cylindrical Roller Bearing Catalog 10447, North Canton, OH, USA.
About This Type
Cylindrical roller bearings carry high radial loads at high speeds; line contact between rollers and raceways provides much higher radial capacity than a ball bearing of the same size. Typical applications include electric motors, gearboxes, pumps, traction motors and — in double-row designs — machine-tool spindles and rolling mills.
The rib configuration determines the axial behaviour. NU and N designs allow free axial displacement between shaft and housing, so they serve as the floating end where thermal expansion must be absorbed. NJ locates the shaft in one axial direction; NUP — an NJ with a loose rib washer — locates it in both directions and serves as the locating end. Full-complement designs (NCF, SL, NNCF …) fit the maximum number of rollers for the highest radial ratings, at the cost of limiting speed, while the double-row NN and NNU designs sacrifice compactness for rigidity. Unlike tapered roller bearings, cylindrical roller bearings use the CN/C2/C3/C4 clearance groups; the group is selected on the basis of the fits and the temperature gradient.
Inner and outer rings are separable on NU, N, NJ and NUP designs, so each ring can be mounted with its own interference fit — an advantage in tight assemblies. On NUP bearings, the loose rib washer must be fitted on the correct side; on floating-end NU/N arrangements, the fit must prevent creep without blocking axial displacement. Never use an NU or N bearing to locate a shaft axially.
Series note: The N design has no ribs on the outer ring — the mirror of NU — and likewise allows free axial displacement as a floating end.
Related Guides
Disclaimer: Data on this page is compiled from publicly available online sources for reference only, and not every model appears in a manufacturer's published catalog. Values may differ between sources and editions — always verify against the manufacturer's current documentation before design or purchase.Full disclaimer →