61901 bearing: complete specifications & equivalents
The 61901 is a ISO 15 radial bearing sized 12 x 24 x 6 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 12 mm |
| Outer diameter D | 24 mm |
| Width B | 6 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 2.91 kN |
| Basic static load rating C0 | 1.46 kN |
| Fatigue load limit Pu | 0.062 kN |
| Reference speed (thermal) | 67000 rpm |
| Limiting speed (mechanical) | 40000 rpm |
| Operating temperature | -40 to +150 °C |
| Mass | 11 g |
| Manufacturer designation | SKF 61901 |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-25 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-24
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 & 61900-series range
| Bore d | 0.472 in |
|---|---|
| Outer diameter D | 0.945 in |
| Width B | 0.236 in |
| ISO bore code | 01 |
| Radial section height (D−d)/2 | 6 mm |
| Smallest bore in 61900-series | 3 mm |
| Largest outer diameter in 61900-series | 1120 mm |
| Width range across 61900-series | 3–118 mm |
| Bore position in 61900-series (smallest first) | 9 of 63 |
| Bore above smallest 61900-series size | 9 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61901-2RS-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 61901-FAG | FAG | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 61901-ZZ-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 61901 | ISO 15 | full Dimensions and internal design equivalent — standard interchange. | ISO 15 boundary-dimension envelope; standard interchange — confirm clearance class and precision with the supplier. |
| 61901-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 61901-NSK | NSK | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 61901-RSR | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (OPEN vs RSR) — confirm sealing suits the duty. |
| 61901-ZZ-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| 61901-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (OPEN vs 2RS) — confirm sealing suits the duty. |
| 61901-NTN | NTN | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 61901-RSR-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (OPEN vs RSR) — confirm sealing suits the duty. |
| 61901-ZZ-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 12×24×6 mm envelope per ISO 15; seal variant differs (OPEN vs ZZ) — confirm sealing suits the duty. |
| W61901-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 61901-2RS1 shares the 12×24×6 mm envelope but rates differently (2.91/1.46 kN vs 2.51/1.46 kN) — not a load-rating equivalent. |
| W61901-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 61901-2Z shares the 12×24×6 mm envelope but rates differently (2.91/1.46 kN vs 2.51/1.46 kN) — not a load-rating equivalent. |
| W61901 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 61901 shares the 12×24×6 mm envelope but rates differently (2.91/1.46 kN vs 2.51/1.46 kN) — not a load-rating equivalent. |
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 61901 model number is decoded
In the 61900-series (diameter series 9 of ISO 15) the last two digits encode the bore: 61901 carries bore code 01 = 12 mm. Codes 00–03 follow the 10/12/15/17 mm exception table rather than code × 5. Outside diameter 24 mm and width 6 mm come from the ISO 15 boundary-dimensions general plan. With no seal suffix the bearing is open: no shields or seals are fitted and lubrication is supplied by the application. For normal-load mounting with a rotating inner ring on a 12 mm shaft, typical catalogue practice is a j5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. In the SKF catalogue this open execution carries the bare designation; protected variants are ordered separately as -2Z and -2RSH.
Typical equipment & failure modes
Common applications
- space-constrained gearboxes
- clutch and transmission assemblies
- robotics and automation joints
- lay shafts and idler shafts
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- brinelling from static overload or hammering during mounting
- false brinelling from vibration while the shaft is stationary
Selection pitfalls — read before you substitute
- Bore codes 00–03 use the exception table: 61901 fits a 12 mm shaft — the code × 5 mnemonic does not apply below code 04 (it would imply 0 mm for code 00).
- The 619xx thin section at 12 mm bore (6.0 mm section height) cannot shrug off the misalignment a standard section tolerates; keep the housing bores round and aligned, or edge contact will spall the raceways early.
- The open 61901 has no lubricant retention: grease escapes and contaminants migrate straight into the 12×24×6 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Storage matters for open bearings: 61901 leaves the factory with rust preventive only, so clean it and apply the service grease at assembly even if the rings look oily from the wrapper.
- Do not quieten a noisy bearing by preloading it: the 61900-series is a deep-groove design, not angular-contact; axial preload raises temperature and shortens grease life.
- Assign fits by which ring rotates: an interference shaft fit for a rotating inner ring; if the outer ring rotates instead, reverse the logic — a loose rotating ring creeps and frets its seat.
- The open 61901 needs external sealing and application-supplied lubrication; in the SKF catalogue the protected variants are separate order numbers 61901-2Z (shields) and 61901-2RSH (contact seals), not suffix-free 61901.
- The 2.91/1.46 kN ratings here are SKF Explorer-class figures from catalogue PUB BU/P1 17000/1 EN (Oct 2018); SKF can revise internal geometry and ratings without changing the designation, so treat the catalogue version and date as part of the specification and re-verify for critical drives.
Frequently asked questions
What are the dimensions of a 61901 bearing?
A 61901 deep-groove ball bearing has a 12 mm bore, 24 mm outer diameter and 6 mm width (0.472 × 0.945 × 0.236 in), per ISO 15 boundary dimensions. It is an open bearing with no seals or shields.
What lubrication does 61901 need?
The open 61901 is lubricated by the application; a NLGI 2 lithium-soap grease filled to roughly 25–35% of the free volume is the common choice, with a defined relubrication interval.
Why does 61901 not follow the bore-code × 5 rule?
Codes 00–03 use the exception table (10, 12, 15 and 17 mm): 61901 with code 01 has a 12 mm bore. The code × 5 convention starts at code 04 (20 mm).
What does no suffix on 61901 mean?
A bare 61901 designation means open: no shields or seals, normal CN radial clearance and P0 normal tolerance unless further suffixes are ordered. The application must supply and retain the lubrication.
What is the SKF designation and catalogue data for 61901?
In the SKF Rolling Bearings catalogue this size is listed as 61901 — the open (unsealed) execution, 12×24×6 mm per ISO 15. Quoted values: C 2.91 kN, C0 1.46 kN, Pu 0.062 kN, limiting speed 40000 r/min, mass 11 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 61901.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-25. Read our editorial & correction policy.