W6306-ZZ bearing: complete specifications & equivalents
The W6306-ZZ is a ISO 15 radial bearing sized 30 x 72 x 19 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 | 30 mm |
| Outer diameter D | 72 mm |
| Width B | 19 mm |
| Material | SS440C |
| Seal / shield | ZZ |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 22.9 kN |
| Basic static load rating C0 | 15 kN |
| Fatigue load limit Pu | 0.64 kN |
| Reference speed (thermal) | 22000 rpm |
| Limiting speed (mechanical) | 11000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 345 g |
| Manufacturer designation | W 6306-2Z |
| 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 & 6300-series range
| Bore d | 1.181 in |
|---|---|
| Outer diameter D | 2.835 in |
| Width B | 0.748 in |
| ISO bore code | 06 |
| Radial section height (D−d)/2 | 21 mm |
| Smallest bore in 6300-series | 2 mm |
| Largest outer diameter in 6300-series | 500 mm |
| Width range across 6300-series | 3–95 mm |
| Bore position in 6300-series (smallest first) | 13 of 40 |
| Bore above smallest 6300-series size | 28 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| W6306-2RS | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 30×72×19 mm envelope and equivalent catalogue ratings; W 6306-2RS1 is the two contact elastomer seals execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
| W6306 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 30×72×19 mm envelope and equivalent catalogue ratings; W 6306 is the open arrangement execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
| 306 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×72×19 mm envelope, but the stainless and chrome-steel executions carry different catalogue ratings (22.9/15 kN vs 29.7/21.6 kN) — envelope match, not a load-rating equivalent; choose by corrosion versus load duty. |
| 306-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×72×19 mm envelope, but the stainless and chrome-steel executions carry different catalogue ratings (22.9/15 kN vs 29.7/21.6 kN) — envelope match, not a load-rating equivalent; choose by corrosion versus load duty. |
| 6306 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 6306 shares the 30×72×19 mm envelope but carries different catalogue ratings (22.9/15 kN vs 29.6/16 kN) — the stainless execution is not a load-rating equivalent. |
| 6306-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 6306-2Z shares the 30×72×19 mm envelope but carries different catalogue ratings (22.9/15 kN vs 29.6/16 kN) — the stainless execution is not a load-rating equivalent. |
| 6306-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 6306-2RSH shares the 30×72×19 mm envelope but carries different catalogue ratings (22.9/15 kN vs 29.6/16 kN) — the stainless execution is not a load-rating equivalent. |
| 6306-RSR | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 6306-2RZ shares the 30×72×19 mm envelope but carries different catalogue ratings (22.9/15 kN vs 29.6/16 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 W6306-ZZ model number is decoded
The W prefix denotes SKF stainless steel deep-groove bearings (X108CrMo17 / AISI 440C class rings). In the 6300-series, the last two digits encode the bore: 6306 carries code 06 = 30 mm (code × 5). Envelope 30×72×19 mm (1.181×2.835×0.748 in), C 22.9 kN, C0 15 kN, Pu 0.64 kN; limiting speed 11000 r/min and mass 345 g. SKF spells the double shield W 6306-2Z (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
- 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
- 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
- Stainless bearings carry lower load ratings than chrome steel of the same envelope: W6306-ZZ is quoted at C 22.9 kN versus the 19 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 W6306-ZZ; standard fill is industrial grease unless specified otherwise.
- Corrosion resistance depends on clean, undamaged surfaces: never weld near W6306-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 W6306-ZZ inside the quoted grease temperature range.
- Catalogue ratings for W6306-ZZ (C 22.9 kN, C0 15 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.
- Clearance suffixes follow the seal code in the designation stack (e.g. W 6306-2Z/C3 in SKF spelling); no suffix means normal CN internal clearance.
Frequently asked questions
What are the dimensions of the stainless W6306-ZZ?
SKF W 6306-2Z measures 30×72×19 mm (1.181×2.835×0.748 in), about 345 g, C 22.9 kN.
What does the W in W 6306-2Z 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.
What grease is supplied in W6306-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.
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 W6306-ZZ; 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.