W628-8-2RS bearing: complete specifications & equivalents
The W628-8-2RS is a ISO 15 radial bearing sized 8 x 16 x 5 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 | 8 mm |
| Outer diameter D | 16 mm |
| Width B | 5 mm |
| Material | SS440C |
| Seal / shield | 2RS |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 0.715 kN |
| Basic static load rating C0 | 0.3 kN |
| Fatigue load limit Pu | 0.012 kN |
| Limiting speed (mechanical) | 26000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 3.85 g |
| Manufacturer designation | W 628/8-2RS1 |
| 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 & 62800-series range
| Bore d | 0.315 in |
|---|---|
| Outer diameter D | 0.63 in |
| Width B | 0.197 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 4 mm |
| Smallest bore in 62800-series | 5 mm |
| Largest outer diameter in 62800-series | 24 mm |
| Width range across 62800-series | 4–8 mm |
| Bore position in 62800-series (smallest first) | 4 of 5 |
| Bore above smallest 62800-series size | 3 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 628-8-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 8×16×5 mm envelope, but the stainless and chrome-steel executions carry different catalogue ratings (0.715/0.3 kN vs 1.33/0.57 kN) — envelope match, not a load-rating equivalent; choose by corrosion versus load duty. |
| 628-8-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 8×16×5 mm envelope, but the stainless and chrome-steel executions carry different catalogue ratings (0.715/0.3 kN vs 1.33/0.57 kN) — envelope match, not a load-rating equivalent; choose by corrosion versus load duty. |
| W628-8-ZZ | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 8×16×5 mm envelope and equivalent catalogue ratings; W 628/8-2Z is the two non-contact shields execution of this size — boundary dimensions interchangeable, only the seal/shield/cage execution differs. |
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 W628-8-2RS model number is decoded
The W prefix denotes SKF stainless steel deep-groove bearings (X108CrMo17 / AISI 440C class rings). In the 62800-series, the bore is written directly after the slash as 8 mm (bores below 10 mm use the slash spelling). Envelope 8×16×5 mm (0.315×0.63×0.197 in), C 0.715 kN, C0 0.3 kN, Pu 0.012 kN; limiting speed 26000 r/min and mass 3.85 g. SKF catalogues the sealed execution as W 628/8-2RS1: 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
- 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
- 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
- The stainless steel is martensitic and MAGNETIC; do not reject W628-8-2RS 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: W628-8-2RS is quoted at C 0.715 kN versus the 5 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 W628-8-2RS; standard fill is industrial grease unless specified otherwise.
- Corrosion resistance depends on clean, undamaged surfaces: never weld near W628-8-2RS or scratch the raceways during mounting, since the damaged spot starts corrosion.
- Deep-groove geometry tolerates only minutes of misalignment; if the 16 mm housing bore cannot be aligned, move to a self-aligning bearing rather than shimming W628-8-2RS.
- Do not preload W628-8-2RS to silence it: a deep-groove ball bearing is not angular-contact, and axial preload only raises temperature and shortens grease life.
Frequently asked questions
What are the dimensions of the stainless W628-8-2RS?
SKF W 628/8-2RS1 measures 8×16×5 mm (0.315×0.63×0.197 in), about 3.85 g, C 0.715 kN.
What does the W in W 628/8-2RS1 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 W628-8-2RS?
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 W628-8-2RS; 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.