W61908-2RS bearing: complete specifications & equivalents
The W61908-2RS is a ISO 15 radial bearing sized 40 x 62 x 12 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 | 62 mm |
| Width B | 12 mm |
| Material | SS440C |
| Seal / shield | 2RS |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 11.9 kN |
| Basic static load rating C0 | 9.8 kN |
| Fatigue load limit Pu | 0.425 kN |
| Limiting speed (mechanical) | 6700 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 107 g |
| Manufacturer designation | W 61908-2RS1 |
| 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 & 61900-series range
| Bore d | 1.575 in |
|---|---|
| Outer diameter D | 2.441 in |
| Width B | 0.472 in |
| ISO bore code | 08 |
| Radial section height (D−d)/2 | 11 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) | 16 of 63 |
| Bore above smallest 61900-series size | 37 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61908-ZZ | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | NSK NSK 6908ZZ shares the 40×62×12 mm envelope but carries different catalogue ratings (11.9/9.8 kN vs 15/10 kN) — the stainless execution is not a load-rating equivalent. |
| 61908 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61908 shares the 40×62×12 mm envelope but carries different catalogue ratings (11.9/9.8 kN vs 13.8/10 kN) — the stainless execution is not a load-rating equivalent. |
| 61908-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61908-2RS1 shares the 40×62×12 mm envelope but carries different catalogue ratings (11.9/9.8 kN vs 13.8/10 kN) — the stainless execution is not a load-rating equivalent. |
| 61908-RSR | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61908-2RZ shares the 40×62×12 mm envelope but carries different catalogue ratings (11.9/9.8 kN vs 13.8/10 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 W61908-2RS 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: 61908 carries code 08 = 40 mm (code × 5). Envelope 40×62×12 mm (1.575×2.441×0.472 in), C 11.9 kN, C0 9.8 kN, Pu 0.425 kN; limiting speed 6700 r/min and mass 107 g. SKF catalogues the sealed execution as W 61908-2RS1: two contact elastomer lips (2RS1/2RSH spelling) over a lifetime grease fill; the lips add drag, and no reference (thermal) speed is published. 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
- pharmaceutical and packaging machines
- washdown-duty equipment
- chemical and marine atmospheres
- medical and laboratory devices
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
- contact-seal lip hardening and pre-grease loss after long high-temperature service
- grease-life expiry inside the sealed-for-life cavity, which has no relubrication path
Selection pitfalls — read before you substitute
- Corrosion resistance depends on clean, undamaged surfaces: never weld near W61908-2RS or scratch the raceways during mounting, since the damaged spot starts corrosion.
- Temperatures above roughly 300 °C temper the stainless races; even standard greases fail far earlier — keep W61908-2RS 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 — W61908-2RS is not marine-grade stainless.
- The stainless steel is martensitic and MAGNETIC; do not reject W61908-2RS over magnetism — only austenitic grades are non-magnetic, and those are too soft for bearing raceways.
- The fatigue load limit is 0.425 kN; it feeds the equivalent-mean-load check, not the basic life calculation — do not substitute one for the other.
- Deep-groove geometry tolerates only minutes of misalignment; if the 62 mm housing bore cannot be aligned, move to a self-aligning bearing rather than shimming W61908-2RS.
Frequently asked questions
What are the dimensions of the stainless W61908-2RS?
SKF W 61908-2RS1 measures 40×62×12 mm (1.575×2.441×0.472 in), about 107 g, C 11.9 kN.
What does the W in W 61908-2RS1 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 W61908-2RS?
Sealed units are pre-greased for life; for food or pharmaceutical duty order (or re-grease before service) with an NSF H1 registered food-grade grease.
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 W61908-2RS; 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.