W6306 bearing: complete specifications & equivalents
The W6306 is a ISO 15 radial bearing sized 30 x 72 x 19 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 | 72 mm |
| Width B | 19 mm |
| Material | SS440C |
| Seal / shield | open |
| 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) | 14000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 331 g |
| Manufacturer designation | W 6306 |
| 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-ZZ | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 30×72×19 mm envelope and equivalent catalogue ratings; W 6306-2Z is the two non-contact shields 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 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 14000 r/min and mass 331 g. The open W 6306 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
- bicycle and outdoor equipment
- appliances exposed to moisture
- food and beverage conveyors
- pharmaceutical and packaging machines
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
- 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
- Temperatures above roughly 300 °C temper the stainless races; even standard greases fail far earlier — keep W6306 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 — W6306 is not marine-grade stainless.
- The stainless steel is martensitic and MAGNETIC; do not reject W6306 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: W6306 is quoted at C 22.9 kN versus the 19 mm-wide 52100 version — do not swap on dimensions alone.
- Fillet radii must clear the W6306 chamfer so the 19 mm-wide ring seats square; an oversized shaft radius creates point contact on the ring face.
- Deep-groove geometry tolerates only minutes of misalignment; if the 72 mm housing bore cannot be aligned, move to a self-aligning bearing rather than shimming W6306.
Frequently asked questions
What are the dimensions of the stainless W6306?
SKF W 6306 measures 30×72×19 mm (1.181×2.835×0.748 in), about 331 g, C 22.9 kN.
What does the W in W 6306 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 W6306?
The envelope matches, but stainless rates lower (C 22.9 kN for W 6306); 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.