W61805-ZZ bearing: complete specifications & equivalents
The W61805-ZZ is a ISO 15 radial bearing sized 25 x 37 x 7 mm (bore x OD x width) with ZZ sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 25 mm |
| Outer diameter D | 37 mm |
| Width B | 7 mm |
| Material | SS440C |
| Seal / shield | ZZ |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 3.38 kN |
| Basic static load rating C0 | 2.5 kN |
| Fatigue load limit Pu | 0.108 kN |
| Reference speed (thermal) | 38000 rpm |
| Limiting speed (mechanical) | 19000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 21 g |
| Manufacturer designation | W 61805-2Z |
| 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 & 61800-series range
| Bore d | 0.984 in |
|---|---|
| Outer diameter D | 1.457 in |
| Width B | 0.276 in |
| ISO bore code | 05 |
| Radial section height (D−d)/2 | 6 mm |
| Smallest bore in 61800-series | 1 mm |
| Largest outer diameter in 61800-series | 1820 mm |
| Width range across 61800-series | 1–140 mm |
| Bore position in 61800-series (smallest first) | 16 of 74 |
| Bore above smallest 61800-series size | 24 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61805-ZZ | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | NSK NSK 6805ZZ shares the 25×37×7 mm envelope but carries different catalogue ratings (3.38/2.5 kN vs 4.95/3.15 kN) — the stainless execution is not a load-rating equivalent. |
| W61805-2RS | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 25×37×7 mm envelope and equivalent catalogue ratings; W 61805-2RS1 is the two contact elastomer seals execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
| 61805 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61805 shares the 25×37×7 mm envelope but carries different catalogue ratings (3.38/2.5 kN vs 4.36/2.6 kN) — the stainless execution is not a load-rating equivalent. |
| 61805-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61805-2RS1 shares the 25×37×7 mm envelope but carries different catalogue ratings (3.38/2.5 kN vs 4.36/2.6 kN) — the stainless execution is not a load-rating equivalent. |
| 61805-RSR | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61805-2RZ shares the 25×37×7 mm envelope but carries different catalogue ratings (3.38/2.5 kN vs 4.36/2.6 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 W61805-ZZ model number is decoded
The W prefix denotes SKF stainless steel deep-groove bearings (X108CrMo17 / AISI 440C class rings). In the 61800-series, the last two digits encode the bore: 61805 carries code 05 = 25 mm (code × 5). Envelope 25×37×7 mm (0.984×1.457×0.276 in), C 3.38 kN, C0 2.5 kN, Pu 0.108 kN; limiting speed 19000 r/min and mass 21 g. SKF spells the double shield W 61805-2Z (suffix 2Z); the shields are non-contact, retain grease and block coarse debris but are not liquid-tight. 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
- medical and laboratory devices
- small pumps handling corrosive media
- bicycle and outdoor equipment
- appliances exposed to moisture
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
- fine-particle abrasion when non-contact shields let dust through in a dirty environment
- grease aging inside the shielded cavity with no relubrication path
Selection pitfalls — read before you substitute
- Temperatures above roughly 300 °C temper the stainless races; even standard greases fail far earlier — keep W61805-ZZ 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 — W61805-ZZ is not marine-grade stainless.
- The stainless steel is martensitic and MAGNETIC; do not reject W61805-ZZ 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: W61805-ZZ is quoted at C 3.38 kN versus the 7 mm-wide 52100 version — do not swap on dimensions alone.
- The fatigue load limit is 0.108 kN; it feeds the equivalent-mean-load check, not the basic life calculation — do not substitute one for the other.
- At 25 mm bore, C3 clearance is the safe choice when interference fits plus temperature rise consume the CN clearance; a hot tight bearing with no residual clearance fails fast.
Frequently asked questions
What are the dimensions of the stainless W61805-ZZ?
SKF W 61805-2Z measures 25×37×7 mm (0.984×1.457×0.276 in), about 21 g, C 3.38 kN.
What does the W in W 61805-2Z 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.
Can I replace a chrome-steel bearing with stainless W61805-ZZ?
The envelope matches, but stainless rates lower (C 3.38 kN for W 61805-2Z); for corrosive environments that trade-off is intended, for high loads it shortens life.
Is the stainless bearing magnetic?
Yes. Bearing stainless steels are martensitic (hardened) and magnetic; non-magnetic austenitic grades cannot be hardened enough for raceways and balls.
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.