W61901 bearing: complete specifications & equivalents
The W61901 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 | SS440C |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 2.51 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 +120 °C |
| Mass | 9.8 g |
| Manufacturer designation | W 61901 |
| 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 & 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-RSR | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | NSK NSK 6901VV shares the 12×24×6 mm envelope but carries different catalogue ratings (2.51/1.46 kN vs 3.2/1.46 kN) — the stainless execution is not a load-rating equivalent. |
| W61901-2RS | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 12×24×6 mm envelope and equivalent catalogue ratings; W 61901-2RS1 is the two contact elastomer seals execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
| W61901-ZZ | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 12×24×6 mm envelope and equivalent catalogue ratings; W 61901-2Z is the two non-contact shields execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
| 61901 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61901 shares the 12×24×6 mm envelope but carries different catalogue ratings (2.51/1.46 kN vs 2.91/1.46 kN) — the stainless execution is not a load-rating equivalent. |
| 61901-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61901-2RS1 shares the 12×24×6 mm envelope but carries different catalogue ratings (2.51/1.46 kN vs 2.91/1.46 kN) — the stainless execution is not a load-rating equivalent. |
| 61901-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61901-2Z shares the 12×24×6 mm envelope but carries different catalogue ratings (2.51/1.46 kN vs 2.91/1.46 kN) — the stainless execution is 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 W61901 model number is decoded
The W prefix denotes SKF stainless steel deep-groove bearings (X108CrMo17 / AISI 440C class rings). In the 61900-series, bore code 01 follows the 10/12/15/17 mm exception table, so 61901 fits a 12 mm shaft. Envelope 12×24×6 mm (0.472×0.945×0.236 in), C 2.51 kN, C0 1.46 kN, Pu 0.062 kN; limiting speed 40000 r/min and mass 9.8 g. The open W 61901 carries no shields or seals and relies on application lubrication and external sealing. Stainless is chosen for corrosion and washdown duty, not for extra load — the same-envelope chrome-steel bearing rates higher.
Typical equipment & failure modes
Common applications
- bicycle and outdoor equipment
- appliances exposed to moisture
- food and beverage conveyors
- pharmaceutical and packaging machines
Known failure patterns
- seal and grease failure before the rings corrode in sustained washdown service
- surface staining and pitting when even the stainless steel is left unlubricated in salty or acidic duty
- contamination wear when the open arrangement is used without external seals
- lubricant starvation where no regreasing interval is maintained
Selection pitfalls — read before you substitute
- Temperatures above roughly 300 °C temper the stainless races; even standard greases fail far earlier — keep W61901 inside the quoted grease temperature range.
- W-prefix stainless rings (X108CrMo17 / AISI 440C class) resist moisture and weak chemicals but will still rust in chloride-rich or salt-spray duty without protection — W61901 is not marine-grade stainless.
- The stainless steel is martensitic and MAGNETIC; do not reject W61901 over magnetism — only austenitic grades are non-magnetic, and those are too soft for bearing raceways.
- Stainless bearings carry lower load ratings than chrome steel of the same envelope: W61901 is quoted at C 2.51 kN versus the 6 mm-wide 52100 version — do not swap on dimensions alone.
- Assign interference to the rotating ring: on a conventional shaft-mounted 12 mm position the inner ring rotates, so use a k5/m6 shaft seat with an H7 housing — reverse the logic if the outer ring rotates.
- Mount by heating the inner ring (max 120 °C) — driving W61901 home through the outer ring or balls brinells the raceways.
Frequently asked questions
What are the dimensions of the stainless W61901?
SKF W 61901 measures 12×24×6 mm (0.472×0.945×0.236 in), about 9.8 g, C 2.51 kN.
What does the W in W 61901 mean?
W is the SKF prefix for stainless steel deep-groove bearings (rings in X108CrMo17 / AISI 440C class); the rest of the designation follows the normal series and bore rules.
Where is W61901 typically used?
Food and packaging machines, pharmaceutical equipment, washdown conveyors, chemical and marine-atmosphere drives and appliances exposed to moisture.
What grease is supplied in W61901?
The open bearing may ship with a rust-preventive film only; specify a food-grade grease for HACCP areas and plan relubrication.
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.