3308-A-2RS1 bearing: complete specifications & equivalents
The 3308-A-2RS1 is a ISO 15 radial bearing sized 40 x 90 x 36.5 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 | 40 mm |
| Outer diameter D | 90 mm |
| Width B | 36.5 mm |
| Material | GCr15 |
| Seal / shield | 2RS |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 64 kN |
| Basic static load rating C0 | 44 kN |
| Fatigue load limit Pu | 1.86 kN |
| Limiting speed (mechanical) | 5000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 930 g |
| Manufacturer designation | 3308 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 | 1.575 in |
|---|---|
| Outer diameter D | 3.543 in |
| Width B | 1.437 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 25 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) | 7 of 20 |
| Bore above smallest 3300-series size | 25 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 3308-DNRCBM | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×90×36.5 mm envelope, but catalogue C/C0 differ between executions (64/44 kN vs 49.4/41.5 kN) — boundary dimensions match, not a load-rating equivalent. |
| 3308-A | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 40×90×36.5 mm envelope with catalogue ratings within 10 %; 3308 A is the stamped steel cage, open arrangement execution of this size — boundary dimensions interchangeable, execution differs. |
| 3308-ATN9 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 40×90×36.5 mm envelope with catalogue ratings within 10 %; 3308 ATN9 is the glass-fibre PA66 cage, open arrangement execution of this size — boundary dimensions interchangeable, execution differs. |
| 3308-DMA | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×90×36.5 mm envelope, but catalogue C/C0 differ between executions (64/44 kN vs 68.9/57 kN) — boundary dimensions match, not a load-rating equivalent. |
| 3308-DTN9 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 40×90×36.5 mm envelope, but catalogue C/C0 differ between executions (64/44 kN vs 68.9/57 kN) — boundary dimensions match, not a load-rating equivalent. |
| 3308-A-2Z | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 40×90×36.5 mm envelope with catalogue ratings within 10 %; 3308 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 3308-A-2RS1 model number is decoded
3308 A-2RS1 is the capped double-row angular-contact ball bearing for a 40 mm shaft, 40×90×36.5 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 40×90×36.5 mm (1.575×3.543×1.437 in), 25.0 mm radial section height, C 64 kN, C0 44 kN, Pu 1.86 kN.SKF publishes only the 5,000 r/min limiting speed for this execution, catalogue mass 930 g. Speed planning distinguishes the two published ceilings mechanically: the cage and balls tolerate 5,000 r/min and no separate thermal reference is published; at dm ≈ 65.0 mm the corresponding dn is approximately 325k mm·r/min. At the printed limiting speed of 5,000 r/min the mean pitch diameter dm ≈ 65.0 mm implies a dn value around 325k mm·r/min; only the limiting speed is published for this execution. Speed-ratio note for this exact unit: no thermal reference speed is listed (seal/grease life governs), so the 5,000 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
- fan and blower positions
- material-handling equipment
- lifetime-lubricated electric motor and gearbox positions
Known failure patterns
- contact-seal lip hardening and grease-life expiry after long high-temperature service
- fine dust or moisture bypassing a worn 2RS1 lip in dirty or wet duty
- seal-lip wear and grease loss after fine abrasive dust reaches the lip contact
- false brinelling on the loaded row while the shaft stands idle under vibration
- mounting score marks when the bearing is cocked over a burr or keyway
- mounting score marks when the bearing is cocked over a burr or keyway
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.
- The shields/seals do not make the bearing waterproof under immersion or pressure washing; select external sealing for wet or wash-down duty.
- The shields/seals do not make the bearing waterproof under immersion or pressure washing; select external sealing for wet or wash-down duty.
- Never wash 3308-A-2RS1 in solvent: the lifetime grease fill cannot be replaced once flushed out.
- Catalogue ratings are SKF PUB BU/P1 17000 figures for 3308 A-2RS1 as the double contactsealed execution; the other order numbers of the 3308 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 3308-A-2RS1?
3308 A-2RS1 measures 40 mm bore × 90 mm OD × 36.5 mm width (1.575 × 3.543 × 1.437 in), mass about 930 g. SKF 17000 ratings: C 64 kN, C0 44 kN, Pu 1.86 kN, SKF publishes only the 5,000 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 3308-A-2RS1 take?
The same bidirectional combined loads as the open double-row 3308: C 64 kN, C0 44 kN, Pu 1.86 kN. Capping changes sealing and speed, not the basic ratings.
Is 3308-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 5,000 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.