6303-ZZ bearing: complete specifications & equivalents
The 6303-ZZ is a ISO 15 radial bearing sized 17 x 47 x 14 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 | 17 mm |
| Outer diameter D | 47 mm |
| Width B | 14 mm |
| Material | GCr15 |
| Seal / shield | ZZ |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 14.3 kN |
| Basic static load rating C0 | 6.55 kN |
| Fatigue load limit Pu | 0.275 kN |
| Reference speed (thermal) | 34000 rpm |
| Limiting speed (mechanical) | 17000 rpm |
| Operating temperature | -30 to +120 °C |
| Mass | 120 g |
| Manufacturer designation | SKF 6303-2Z |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-25 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-24
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 | 0.669 in |
|---|---|
| Outer diameter D | 1.85 in |
| Width B | 0.551 in |
| ISO bore code | 03 |
| Radial section height (D−d)/2 | 15 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) | 8 of 40 |
| Bore above smallest 6300-series size | 15 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6303-2RS-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (ZZ vs 2RS) — confirm sealing suits the duty. |
| 6303-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (ZZ vs OPEN) — confirm sealing suits the duty. |
| 6303-ZZ-FAG | FAG | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 6303-2RS | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (ZZ vs 2RS) — confirm sealing suits the duty. |
| 6303-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (ZZ vs OPEN) — confirm sealing suits the duty. |
| 6303-RSR-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (ZZ vs RSR) — confirm sealing suits the duty. |
| 6303-ZZ-NSK | NSK | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 6303-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (ZZ vs 2RS) — confirm sealing suits the duty. |
| 6303-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (ZZ vs OPEN) — confirm sealing suits the duty. |
| 6303-RSR-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 17×47×14 mm envelope per ISO 15; seal variant differs (ZZ vs RSR) — confirm sealing suits the duty. |
| 6303-ZZ-NTN | NTN | full Dimensions and internal design equivalent — standard interchange. | Identical ISO 15 envelope, seal and ratings band — standard interchange; re-verify precision class and clearance per supplier. |
| 7303 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | — |
| W6303-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 6303-2RS1 shares the 17×47×14 mm envelope but rates differently (14.3/6.55 kN vs 11.7/6.55 kN) — not a load-rating equivalent. |
| W6303-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 6303-2Z shares the 17×47×14 mm envelope but rates differently (14.3/6.55 kN vs 11.7/6.55 kN) — not a load-rating equivalent. |
| W6303 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 6303 shares the 17×47×14 mm envelope but rates differently (14.3/6.55 kN vs 11.7/6.55 kN) — 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 6303-ZZ model number is decoded
6303-ZZ carries two non-contact sheet-steel shields that hold the factory grease in and keep coarse debris out; they do not seal against liquids. Within the medium 63xx section (diameter series 3 of ISO 15), its bore code 03 comes from the 10/12/15/17 mm exception table, giving a 17 mm bore; the 47 mm outside diameter and 14 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 17 mm shaft under normal load, catalogue practice seats it on a j5 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. SKF's own suffix is 2Z (this page's industry-neutral spelling is -ZZ); catalogue number 6303-2Z.
Typical equipment & failure modes
Common applications
- domestic appliances
- power tools
- small fans and blowers
- garden equipment
Known failure patterns
- fine-particle abrasion when non-contact shields let dust past in dirty duty
- grease aging in the shield-for-life cavity with no relubrication path
- rolling-contact fatigue spalling after the rated L10 life is exceeded
- brinelling from static overload or hammering during mounting
Selection pitfalls — read before you substitute
- Miniature bearings like 6303-ZZ (17 mm bore) brinell under surprisingly small pressing force; use a fitting sleeve on the ring being mounted and never let the assembly load cross the balls.
- The 63xx medium section at 17 mm bore gains dynamic rating through larger rolling elements on a 47 mm OD; the penalty is mass and a lower limiting speed than the 6203 — do not specify it for speed-critical shafts.
- ZZ shields are non-contact: 6303-ZZ blocks chips and coarse dust but is not waterproof — do not install it expecting a pressure-wash seal, step up to 6303-2RS for that.
- Shielded 6303-ZZ units are typically greased for life; prying the shields out for regreasing usually bends them and leaves a gap that throws grease in service.
- Suffixes stack in a defined order — clearance follows the seal code, e.g. 6303-C3. No clearance suffix means normal CN clearance.
- Measure the shaft, do not trust the drawing: a 17 mm nominal journal worn by even 0.02 mm turns an interference seat into a creeping fit that frets the bore of 6303-ZZ.
- SKF spells the shielded version 6303-2Z (one shield: 6303-Z), not "-ZZ": the suffix language differs by brand even though the ISO envelope is identical, so quote the brand designation when ordering.
- The single-shield execution 6303-Z is a distinct order number in catalogue 17000: it suits open gears or oil-bath arrangements where the unshielded face faces the lubricant, and it is not interchangeable with the double-shield 6303-2Z for high-contamination positions.
- The 14.3/6.55 kN ratings here are SKF Explorer-class figures from catalogue PUB BU/P1 17000/1 EN (Oct 2018); SKF can revise internal geometry and ratings without changing the designation, so treat the catalogue version and date as part of the specification and re-verify for critical drives.
Frequently asked questions
What are the dimensions of a 6303-ZZ bearing?
A 6303-ZZ deep-groove ball bearing has a 17 mm bore, 47 mm outer diameter and 14 mm width (0.669 × 1.85 × 0.551 in), per ISO 15 boundary dimensions. It is fitted with two non-contact metallic shields.
What internal clearance does 6303-ZZ have?
Unless a clearance suffix says otherwise, 6303-ZZ is manufactured to normal (CN) radial internal clearance. Tight fits and hot shafts consume clearance in service — for those conditions order the C3 execution of 6303 and verify the residual clearance after mounting.
How should 6303-ZZ be mounted?
Apply the mounting force to the ring being fitted: on a 17 mm shaft seat the press load must pass through the inner-ring face only. A fitting sleeve and an arbor press are normally sufficient at this size. Never strike the outer ring, the cage or the seals.
What lubrication does 6303-ZZ need?
6303-ZZ is greased at the factory and the shields hold the fill for the bearing's service life; relubrication is not intended, and adding grease through the shield gap usually forces dirt in with it.
What is the SKF designation and catalogue data for 6303-ZZ?
In the SKF Rolling Bearings catalogue this size is listed as 6303-2Z — two non-contact sheet-metal shields, 17×47×14 mm per ISO 15. Quoted values: C 14.3 kN, C0 6.55 kN, Pu 0.275 kN, limiting speed 17000 r/min, mass 120 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 6303-ZZ.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-25. Read our editorial & correction policy.