6306-RSR bearing: complete specifications & equivalents
The 6306-RSR is a ISO 15 radial bearing sized 30 x 72 x 19 mm (bore x OD x width) with RSR 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 | GCr15 |
| Seal / shield | RSR |
| Internal clearance | CN / C3 available |
| Tolerance class | P0 |
| Cage | steel, stamped ribbon (J-type) |
| Basic dynamic load rating C | 29.6 kN |
| Basic static load rating C0 | 16 kN |
| Fatigue load limit Pu | 0.67 kN |
| Reference speed (thermal) | 20000 rpm |
| Limiting speed (mechanical) | 11000 rpm |
| Operating temperature | -30 to +120 °C |
| Mass | 360 g |
| Manufacturer designation | SKF 6306-2RZ |
| 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 | 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 |
Mounting, lubrication & life for 6306-RSR
Recommended fits & mounting
- Rotating inner ring on a 30 mm shaft: k5; housing bore H7 for normal stationary-load outer rings. Reverse the logic if the outer ring rotates.
- Fit by induction heating (max 120 °C) where practical — never drive the ring home through the rolling elements.
- Keep shaft and housing fillet radii below the bearing chamfer so the 19 mm-wide ring seats square on its shoulder.
Lubrication strategy
Non-contact low-drag seal lips retain the factory grease but are not liquid-tight. Treat as grease-for-life in light, dry duty; in dirty or wet positions plan replacement around contamination rather than fatigue.
Worked L10 life example (illustrative duty)
For ball bearings, L10h = (C/P)3 · 106 / (60·n). Taking an example radial equivalent load P = 3 kN at n = 1,500 r/min (a small belted motor duty — substitute the real equivalent load from the application calculation):
C = 29.6 kN → L10h ≈ 10,673 hours
Choosing a section at the same 30 mm bore
| Series | Open execution | OD × width | C (kN) | Limiting speed (r/min) |
|---|---|---|---|---|
| 60xx | 6006-FAG | 55 × 13 | 14.5 | 20,100 |
| 62xx | 6206-FAG | 62 × 16 | 22.0 | 17,800 |
| 63xx | 6306-FAG | 72 × 19 | 32.0 | 15,100 |
| 64xx | 6406-FAG | 90 × 23 | 42.5 | 11,000 |
| 618xx | 61806-FAG | 42 × 7 | 4.5 | 24,500 |
| 619xx | 61906-FAG | 47 × 9 | 7.2 | 21,700 |
| 160xx | 16006 | 55 × 9 | 11.2 | 18,500 |
A larger section is not a drop-in swap — OD and width change — and same-envelope seal variants are compared on the 30×72×19 envelope page. Match meaning, not the size chart alone: see what the cross-reference levels mean.
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 6306-2RS-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×72×19 mm envelope per ISO 15; seal variant differs (RSR vs 2RS) — confirm sealing suits the duty. |
| 6306-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×72×19 mm envelope per ISO 15; seal variant differs (RSR vs OPEN) — confirm sealing suits the duty. |
| 6306-ZZ-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×72×19 mm envelope per ISO 15; seal variant differs (RSR vs ZZ) — confirm sealing suits the duty. |
| 6306 | ISO 15 | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range before substituting. |
| 6306-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×72×19 mm envelope per ISO 15; seal variant differs (RSR vs 2RS) — confirm sealing suits the duty. |
| 6306-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×72×19 mm envelope per ISO 15; seal variant differs (RSR vs OPEN) — confirm sealing suits the duty. |
| 6306-RSR-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. |
| 6306-ZZ-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×72×19 mm envelope per ISO 15; seal variant differs (RSR vs ZZ) — confirm sealing suits the duty. |
| 6306-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×72×19 mm envelope per ISO 15; seal variant differs (RSR vs 2RS) — confirm sealing suits the duty. |
| 6306-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×72×19 mm envelope per ISO 15; seal variant differs (RSR vs OPEN) — confirm sealing suits the duty. |
| 6306-RSR-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. |
| 6306-ZZ-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 30×72×19 mm envelope per ISO 15; seal variant differs (RSR vs ZZ) — confirm sealing suits the duty. |
| 7306 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | — |
| NU306 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | — |
| W6306-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 6306-2RS1 shares the 30×72×19 mm envelope but rates differently (29.6/16 kN vs 22.9/15 kN) — not a load-rating equivalent. |
| W6306-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 6306-2Z shares the 30×72×19 mm envelope but rates differently (29.6/16 kN vs 22.9/15 kN) — not a load-rating equivalent. |
| W6306 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 6306 shares the 30×72×19 mm envelope but rates differently (29.6/16 kN vs 22.9/15 kN) — not a load-rating equivalent. |
| 306 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF 306 shares the 30×72×19 mm envelope but catalogue C/C0 differ — envelope match only after a load check. |
| 306-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF 306-2Z shares the 30×72×19 mm envelope but catalogue C/C0 differ — envelope match only after a load check. |
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 6306-RSR model number is decoded
In the 6300-series (diameter series 3 of ISO 15) the last two digits encode the bore: 6306 carries bore code 06 = 30 mm. Outside diameter 72 mm and width 19 mm come from the ISO 15 boundary-dimensions general plan. Suffix -RSR denotes two low-friction non-contact elastomer seals; they keep coarse debris out with minimal drag but are not liquid-tight. For normal-load mounting with a rotating inner ring on a 30 mm shaft, typical catalogue practice is a k5 shaft seat with an H7 housing bore — verify against the actual load direction and magnitude. SKF's low-friction seal suffix is 2RSL/2RZ (this page's industry-neutral spelling is -RSR); catalogue number 6306-2RZ.
Typical equipment & failure modes
Common applications
- fans and blowers
- electric motors
- centrifugal pumps
- small gearboxes
Known failure patterns
- ingress of fine dust or moisture past the non-contact lip in dirty or wet duty (RSR is not liquid-tight)
- lip-lubricant starvation if the bearing runs dry for extended periods
- brinelling from static overload or hammering during mounting
- false brinelling from vibration while the shaft is stationary
Selection pitfalls — read before you substitute
- Sizes around 30 mm bore are normally pressed on cold with a sleeve against the inner-ring face; the press force must never route through the outer ring or the balls of 6306-RSR.
- The 63xx medium series gains rating at 30 mm bore through a 72 mm OD and 19 mm width; the heavier rolling elements also trade away some speed versus a 6206.
- RSR low-friction seals on 6306-RSR run faster than contact-seal 6306-2RS but let fine dust and moisture past the non-contact lip; in dirty or wet duty specify 6306-2RS instead.
- The low-drag lip of 6306-RSR barely touches the inner ring; after long shelf storage the grease can separate, so rotate the rings by hand and confirm smooth, silent running before fitting.
- Suffixes stack in a defined order — clearance follows the seal code, e.g. 6306-C3. No clearance suffix means normal CN clearance.
- Never mix components between two 6306-RSR units: rings, cage and balls are factory-matched and are not field-interchangeable, even between identical designations.
- SKF catalogues the low-friction seal as 6306-2RZ (suffix -2RSL or -2RZ): a non-contact elastomer lip that runs near the open 11000 r/min limiting speed, closer to the open bearing's 20000 r/min reference than the contact-seal version. It keeps coarse debris out without the drag of a contact seal, but is not liquid-tight — use 2RSH for wet or fine-dust positions.
- The 29.6/16 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 6306-RSR bearing?
A 6306-RSR deep-groove ball bearing has a 30 mm bore, 72 mm outer diameter and 19 mm width (1.181 × 2.835 × 0.748 in), per ISO 15 boundary dimensions. It is fitted with two low-friction non-contact rubber seals.
What lubrication does 6306-RSR need?
6306-RSR is supplied pre-greased for life and is not designed to be opened for relubrication; where a relubrication path is required, specify the open 6306 with a housing grease fitting instead.
How does the 6306 bore code work?
The last two digits of 6306 are bore code 06, giving 06 × 5 = 30 mm bore. The 72 mm outside diameter and 19 mm width follow the ISO 15 diameter series, not the bore code alone.
What does the RSR suffix on 6306-RSR mean?
RSR means two low-friction non-contact rubber seals. They keep coarse debris out with minimal drag (speed close to the open bearing) but are not liquid-tight; use -2RS contact seals for wet or fine-dust environments.
What is the SKF designation and catalogue data for 6306-RSR?
In the SKF Rolling Bearings catalogue this size is listed as 6306-2RZ — two low-friction non-contact elastomer seals, 30×72×19 mm per ISO 15. Quoted values: C 29.6 kN, C0 16 kN, Pu 0.67 kN, limiting speed 11000 r/min, mass 360 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 6306-RSR.
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.