3304-A-2RS1 bearing: complete specifications & equivalents
The 3304-A-2RS1 is a ISO 15 radial bearing sized 20 x 52 x 22.2 mm (bore x OD x width) with 2RS sealing. 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 | 22.2 mm |
| Material | GCr15 |
| Seal / shield | 2RS |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 23.6 kN |
| Basic static load rating C0 | 14.6 kN |
| Fatigue load limit Pu | 0.62 kN |
| Limiting speed (mechanical) | 9000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 220 g |
| Manufacturer designation | 3304 A-2RS1 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-27
Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); 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 & 3300-series range
| Bore d | 0.787 in |
|---|---|
| Outer diameter D | 2.047 in |
| Width B | 0.874 in |
| ISO bore code | 04 |
| Radial section height (D−d)/2 | 16 mm |
| Smallest bore in 3300-series | 15 mm |
| Largest outer diameter in 3300-series | 240 mm |
| Width range across 3300-series | 19–92.1 mm |
| Bore position in 3300-series (smallest first) | 3 of 20 |
| Bore above smallest 3300-series size | 5 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 3304-A | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 20×52×22.2 mm envelope with catalogue ratings within 10 %; 3304 A is the stamped steel cage, open arrangement execution of this size — boundary dimensions interchangeable, execution differs. |
| 3304-ATN9 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 20×52×22.2 mm envelope with catalogue ratings within 10 %; 3304 ATN9 is the glass-fibre PA66 cage, open arrangement execution of this size — boundary dimensions interchangeable, execution differs. |
| 3304-A-2Z | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 20×52×22.2 mm envelope with catalogue ratings within 10 %; 3304 A-2Z is the stamped steel cage, shields (-2Z) execution of this size — boundary dimensions interchangeable, execution differs. |
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 3304-A-2RS1 model number is decoded
3304 A-2RS1 is the capped double-row angular-contact ball bearing for a 20 mm shaft, 20×52×22.2 mm, greased and sealed (or shielded) for life at the SKF works. A on this double-row bearing means no filling slots, so both ball rows retain their full complement. -2RS1 marks a contact NBR elastomer seal on each side, riding the inner ring: better fine-dust and moisture protection than a shield at the cost of seal drag and a lower speed ceiling. Envelope 20×52×22.2 mm (0.787×2.047×0.874 in), 16.0 mm radial section height, C 23.6 kN, C0 14.6 kN, Pu 0.62 kN.SKF publishes only the 9,000 r/min limiting speed for this execution, catalogue mass 220 g. At the printed limiting speed of 9,000 r/min the mean pitch diameter dm ≈ 36.0 mm implies a dn value around 324k mm·r/min; only the limiting speed is published for this execution. Speed planning distinguishes the two published ceilings mechanically: the cage and balls tolerate 9,000 r/min and no separate thermal reference is published; at dm ≈ 36.0 mm the corresponding dn is approximately 324k mm·r/min. Speed-ratio note for this exact unit: no thermal reference speed is listed (seal/grease life governs), so the 9,000 r/min limiting value is the single published ceiling. Contact-seal execution note: the two NBR -2RS1 lips ride the inner-ring lands, sealing the factory grease against moisture and fine dust; the lips add running torque and set the lower limiting speed printed for this size, and the sealed cavity is maintenance-free by design (no relubrication path). The A-2Z shielded order number is the low-drag alternative for cleaner positions.
Typical equipment & failure modes
Common applications
- textile and office machinery
- conveyor idlers and small drives
- domestic-appliance motors
Known failure patterns
- fine dust or moisture bypassing a worn 2RS1 lip in dirty or wet duty
- shield rubbing after misalignment or overheating of a 2Z execution
- seal-lip wear and grease loss after fine abrasive dust reaches the lip contact
- tilted mounting that loads one double row more heavily than the other
- edge loading from shaft deflection or housing misalignment
- edge loading from shaft deflection or housing misalignment
Selection pitfalls — read before you substitute
- The contact NBR seals add drag and a lower speed ceiling: no relubrication is provided for, so mounting cleanliness decides much of the real grease life.
- Open 3304 and capped 3304-A-2RS1 share the 20×52×22.2 mm envelope and 23.6/14.6 kN ratings — the choice is maintenance access and contamination, not capacity.
- The shields/seals do not make the bearing waterproof under immersion or pressure washing; select external sealing for wet or wash-down duty.
- Fit and fillet rules are unchanged from the open double-row 3304: k5 on a 20 mm rotating shaft, radii clearing the chamfer.
- Catalogue ratings are SKF PUB BU/P1 17000 figures for 3304 A-2RS1 as the double contactsealed execution; the other order numbers of the 3304 size are different products and may carry different ratings — always quote the full designation when purchasing.
Frequently asked questions
What are the dimensions and catalogue data of 3304-A-2RS1?
3304 A-2RS1 measures 20 mm bore × 52 mm OD × 22.2 mm width (0.787 × 2.047 × 0.874 in), mass about 220 g. SKF 17000 ratings: C 23.6 kN, C0 14.6 kN, Pu 0.62 kN, SKF publishes only the 9,000 r/min limiting speed for this execution.
What does the A-2RS1 suffix mean?
A on this double-row bearing means no filling slots, so both ball rows retain their full complement. -2RS1 marks a contact NBR elastomer seal on each side, riding the inner ring: better fine-dust and moisture protection than a shield at the cost of seal drag and a lower speed ceiling.
What loads can 3304-A-2RS1 take?
The same bidirectional combined loads as the open double-row 3304: C 23.6 kN, C0 14.6 kN, Pu 0.62 kN. Capping changes sealing and speed, not the basic ratings.
Is 3304-A-2RS1 sealed for life?
Yes — the two -2RS1 contact NBR seals enclose a lifetime grease fill; there is no relubrication provision, and the seals cap the limiting speed at 9,000 r/min.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-27. Read our editorial & correction policy.