W61801-ZZ bearing: complete specifications & equivalents
The W61801-ZZ is a ISO 15 radial bearing sized 12 x 21 x 5 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 | 12 mm |
| Outer diameter D | 21 mm |
| Width B | 5 mm |
| Material | SS440C |
| Seal / shield | ZZ |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 1.51 kN |
| Basic static load rating C0 | 0.9 kN |
| Fatigue load limit Pu | 0.039 kN |
| Reference speed (thermal) | 70000 rpm |
| Limiting speed (mechanical) | 36000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 5.7 g |
| Manufacturer designation | W 61801-2Z |
| 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 | 0.472 in |
|---|---|
| Outer diameter D | 0.827 in |
| Width B | 0.197 in |
| ISO bore code | 01 |
| Radial section height (D−d)/2 | 4.5 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) | 12 of 74 |
| Bore above smallest 61800-series size | 11 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 61801-RSR | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | NSK NSK 6801VV shares the 12×21×5 mm envelope but carries different catalogue ratings (1.51/0.9 kN vs 2.11/1.04 kN) — the stainless execution is not a load-rating equivalent. |
| W61801-2RS | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 12×21×5 mm envelope and equivalent catalogue ratings; W 61801-2RS1 is the two contact elastomer seals execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
| 61801 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61801 shares the 12×21×5 mm envelope but carries different catalogue ratings (1.51/0.9 kN vs 1.74/0.915 kN) — the stainless execution is not a load-rating equivalent. |
| 61801-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61801-2RS1 shares the 12×21×5 mm envelope but carries different catalogue ratings (1.51/0.9 kN vs 1.74/0.915 kN) — the stainless execution is not a load-rating equivalent. |
| 61801-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 61801-2Z shares the 12×21×5 mm envelope but carries different catalogue ratings (1.51/0.9 kN vs 1.74/0.915 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 W61801-ZZ model number is decoded
The W prefix denotes SKF stainless steel deep-groove bearings (X108CrMo17 / AISI 440C class rings). In the 61800-series, bore code 01 follows the 10/12/15/17 mm exception table, so 61801 fits a 12 mm shaft. Envelope 12×21×5 mm (0.472×0.827×0.197 in), C 1.51 kN, C0 0.9 kN, Pu 0.039 kN; limiting speed 36000 r/min and mass 5.7 g. SKF spells the double shield W 61801-2Z (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
- food and beverage conveyors
- pharmaceutical and packaging machines
- washdown-duty equipment
- chemical and marine atmospheres
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
- Food, pharmaceutical and washdown positions need food-grade grease (e.g. NSF H1 registered) inside W61801-ZZ; standard fill is industrial grease unless specified otherwise.
- Corrosion resistance depends on clean, undamaged surfaces: never weld near W61801-ZZ 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 W61801-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 — W61801-ZZ is not marine-grade stainless.
- Deep-groove geometry tolerates only minutes of misalignment; if the 21 mm housing bore cannot be aligned, move to a self-aligning bearing rather than shimming W61801-ZZ.
- Catalogue ratings for W61801-ZZ (C 1.51 kN, C0 0.9 kN) are SKF figures from PUB BU/P1 17000; geometry revisions can change ratings without changing the designation, so keep the catalogue edition with the specification.
Frequently asked questions
What are the dimensions of the stainless W61801-ZZ?
SKF W 61801-2Z measures 12×21×5 mm (0.472×0.827×0.197 in), about 5.7 g, C 1.51 kN.
What does the W in W 61801-2Z 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.
Where is W61801-ZZ 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 W61801-ZZ?
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.
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.