6305-RSR bearing: complete specifications & equivalents
The 6305-RSR is a ISO 15 radial bearing sized 25 x 62 x 17 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 | 25 mm |
| Outer diameter D | 62 mm |
| Width B | 17 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 | 23.4 kN |
| Basic static load rating C0 | 11.6 kN |
| Fatigue load limit Pu | 0.49 kN |
| Reference speed (thermal) | 24000 rpm |
| Limiting speed (mechanical) | 13000 rpm |
| Operating temperature | -30 to +120 °C |
| Mass | 230 g |
| Manufacturer designation | SKF 6305-2RZ |
| 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 | 0.984 in |
|---|---|
| Outer diameter D | 2.441 in |
| Width B | 0.669 in |
| ISO bore code | 05 |
| Radial section height (D−d)/2 | 18.5 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) | 11 of 40 |
| Bore above smallest 6300-series size | 23 mm |
Mounting, lubrication & life for 6305-RSR
Recommended fits & mounting
- Rotating inner ring on a 25 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 17 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 = 23.4 kN → L10h ≈ 5,273 hours
Choosing a section at the same 25 mm bore
| Series | Open execution | OD × width | C (kN) | Limiting speed (r/min) |
|---|---|---|---|---|
| 60xx | 6005-FAG | 47 × 12 | 12.6 | 23,700 |
| 62xx | 6205-FAG | 52 × 15 | 15.9 | 21,600 |
| 63xx | 6305-FAG | 62 × 17 | 26.5 | 17,800 |
| 64xx | 6405-FAG | 80 × 21 | 36.1 | 12,400 |
| 618xx | 61805-FAG | 37 × 7 | 4.3 | 28,000 |
| 619xx | 61905-FAG | 42 × 9 | 7.0 | 24,200 |
| 160xx | 16005 | 47 × 8 | 8.9 | 22,200 |
A larger section is not a drop-in swap — OD and width change — and same-envelope seal variants are compared on the 25×62×17 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 |
|---|---|---|---|
| 6305-2RS-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 25×62×17 mm envelope per ISO 15; seal variant (RSR vs 2RS) and load ratings differ — confirm sealing and rating before substituting. |
| 6305-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 25×62×17 mm envelope per ISO 15; seal variant (RSR vs OPEN) and load ratings differ — confirm sealing and rating before substituting. |
| 6305-ZZ-FAG | FAG | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 25×62×17 mm envelope per ISO 15; seal variant (RSR vs ZZ) and load ratings differ — confirm sealing and rating before substituting. |
| 6305 | 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. |
| 6305-2RS-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 25×62×17 mm envelope per ISO 15; seal variant differs (RSR vs 2RS) — confirm sealing suits the duty. |
| 6305-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 25×62×17 mm envelope per ISO 15; seal variant differs (RSR vs OPEN) — confirm sealing suits the duty. |
| 6305-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. |
| 6305-ZZ-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 25×62×17 mm envelope per ISO 15; seal variant differs (RSR vs ZZ) — confirm sealing suits the duty. |
| 6305-2RS-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 25×62×17 mm envelope per ISO 15; seal variant differs (RSR vs 2RS) — confirm sealing suits the duty. |
| 6305-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 25×62×17 mm envelope per ISO 15; seal variant differs (RSR vs OPEN) — confirm sealing suits the duty. |
| 6305-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. |
| 6305-ZZ-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 25×62×17 mm envelope per ISO 15; seal variant differs (RSR vs ZZ) — confirm sealing suits the duty. |
| 7305 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | — |
| NU305 | SKF | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | — |
| W6305-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 6305-2RS1 shares the 25×62×17 mm envelope but rates differently (23.4/11.6 kN vs 17.8/11.2 kN) — not a load-rating equivalent. |
| W6305-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 6305-2Z shares the 25×62×17 mm envelope but rates differently (23.4/11.6 kN vs 17.8/11.2 kN) — not a load-rating equivalent. |
| W6305 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF stainless execution W 6305 shares the 25×62×17 mm envelope but rates differently (23.4/11.6 kN vs 17.8/11.2 kN) — not a load-rating equivalent. |
| 305 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF 305 shares the 25×62×17 mm envelope but catalogue C/C0 differ — envelope match only after a load check. |
| 305-ZZ | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF 305-2Z shares the 25×62×17 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 6305-RSR model number is decoded
6305-RSR uses two non-contact elastomer lips with very low drag; coarse debris stays out, but the bearing is not liquid-tight. Within the medium 63xx section (diameter series 3 of ISO 15), multiplying bore code 05 by five gives the 25 mm bore; the 62 mm outside diameter and 17 mm width follow the same boundary-dimension plan. For a rotating inner ring on a 25 mm shaft under normal load, catalogue practice seats it on a k5 shaft fit with an H7 housing bore — confirm against the actual load direction and magnitude before committing. SKF's low-friction seal suffix is 2RSL/2RZ (this page's industry-neutral spelling is -RSR); catalogue number 6305-2RZ.
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
- false brinelling from vibration while the shaft is stationary
- fretting corrosion on a loose shaft seat
Selection pitfalls — read before you substitute
- Sizes around 25 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 6305-RSR.
- The 63xx medium section at 25 mm bore gains dynamic rating through larger rolling elements on a 62 mm OD; the penalty is mass and a lower limiting speed than the 6205 — do not specify it for speed-critical shafts.
- The low-drag lip of 6305-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.
- The non-contact lip of 6305-RSR does not retain a lifetime grease fill the way a contact seal does; confirm the regreasing interval for the 25 mm bore position before relying on it as sealed-for-life.
- Grease compatibility is not guaranteed between fills: mixing lithium and polyurea thickeners in a 6300-series position can soften the mixture and leak — clean out the old fill before switching grease types.
- Assign fits by which ring rotates: an interference shaft fit for a rotating inner ring; if the outer ring rotates instead, reverse the logic — a loose rotating ring creeps and frets its seat.
- SKF catalogues the low-friction seal as 6305-2RZ (suffix -2RSL or -2RZ): a non-contact elastomer lip that runs near the open 13000 r/min limiting speed, closer to the open bearing's 24000 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 23.4/11.6 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 6305-RSR bearing?
A 6305-RSR deep-groove ball bearing has a 25 mm bore, 62 mm outer diameter and 17 mm width (0.984 × 2.441 × 0.669 in), per ISO 15 boundary dimensions. It is fitted with two low-friction non-contact rubber seals.
What lubrication does 6305-RSR need?
6305-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 6305 with a housing grease fitting instead.
How does the 6305 bore code work?
The last two digits of 6305 are bore code 05, giving 05 × 5 = 25 mm bore. The 62 mm outside diameter and 17 mm width follow the ISO 15 diameter series, not the bore code alone.
What does the RSR suffix on 6305-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 6305-RSR?
In the SKF Rolling Bearings catalogue this size is listed as 6305-2RZ — two low-friction non-contact elastomer seals, 25×62×17 mm per ISO 15. Quoted values: C 23.4 kN, C0 11.6 kN, Pu 0.49 kN, limiting speed 13000 r/min, mass 230 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 6305-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.