W61906 bearing: complete specifications & equivalents
The W61906 is a ISO 15 radial bearing sized 30 x 47 x 9 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 30 mm |
| Outer diameter D | 47 mm |
| Width B | 9 mm |
| Material | SS440C |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 6.24 kN |
| Basic static load rating C0 | 5 kN |
| Fatigue load limit Pu | 0.212 kN |
| Reference speed (thermal) | 30000 rpm |
| Limiting speed (mechanical) | 19000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 44 g |
| Manufacturer designation | W 61906 |
| 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 | 1.181 in |
|---|---|
| Outer diameter D | 1.85 in |
| Width B | 0.354 in |
| ISO bore code | 06 |
| Radial section height (D−d)/2 | 8.5 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) | 14 of 63 |
| Bore above smallest 61900-series size | 27 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61906-ZZ | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | NSK NSK 6906ZZ shares the 30×47×9 mm envelope but carries different catalogue ratings (6.24/5 kN vs 7.95/5 kN) — the stainless execution is not a load-rating equivalent. |
| W61906-2RS | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 30×47×9 mm envelope and equivalent catalogue ratings; W 61906-2RS1 is the two contact elastomer seals execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
| 61906 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61906 shares the 30×47×9 mm envelope but carries different catalogue ratings (6.24/5 kN vs 7.28/4.55 kN) — the stainless execution is not a load-rating equivalent. |
| 61906-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61906-2RS1 shares the 30×47×9 mm envelope but carries different catalogue ratings (6.24/5 kN vs 7.28/4.55 kN) — the stainless execution is not a load-rating equivalent. |
| 61906-RSR | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61906-2RZ shares the 30×47×9 mm envelope but carries different catalogue ratings (6.24/5 kN vs 7.28/4.55 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 W61906 model number is decoded
The W prefix denotes SKF stainless steel deep-groove bearings (X108CrMo17 / AISI 440C class rings). In the 61900-series, the last two digits encode the bore: 61906 carries code 06 = 30 mm (code × 5). Envelope 30×47×9 mm (1.181×1.85×0.354 in), C 6.24 kN, C0 5 kN, Pu 0.212 kN; limiting speed 19000 r/min and mass 44 g. The open W 61906 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
- appliances exposed to moisture
- food and beverage conveyors
- pharmaceutical and packaging machines
- washdown-duty equipment
Known failure patterns
- surface staining and pitting when even the stainless steel is left unlubricated in salty or acidic duty
- seal and grease failure before the rings corrode in sustained washdown service
- 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
- 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 — W61906 is not marine-grade stainless.
- The stainless steel is martensitic and MAGNETIC; do not reject W61906 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: W61906 is quoted at C 6.24 kN versus the 9 mm-wide 52100 version — do not swap on dimensions alone.
- Food, pharmaceutical and washdown positions need food-grade grease (e.g. NSF H1 registered) inside W61906; standard fill is industrial grease unless specified otherwise.
- Mount by heating the inner ring (max 120 °C) — driving W61906 home through the outer ring or balls brinells the raceways.
- The fatigue load limit is 0.212 kN; it feeds the equivalent-mean-load check, not the basic life calculation — do not substitute one for the other.
Frequently asked questions
What are the dimensions of the stainless W61906?
SKF W 61906 measures 30×47×9 mm (1.181×1.85×0.354 in), about 44 g, C 6.24 kN.
What does the W in W 61906 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.
What grease is supplied in W61906?
The open bearing may ship with a rust-preventive film only; specify a food-grade grease for HACCP areas and plan relubrication.
Are W stainless bearings waterproof?
No — the stainless rings resist moisture and weak chemicals far better than 52100 chrome steel, but salt spray, strong chlorides and unlubricated washdown duty can still corrode W61906; add seals and food-grade grease for wet positions.
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.