6305-2RS bearing: complete specifications & equivalents
The 6305-2RS is a ISO 15 radial bearing sized 25 x 62 x 17 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 | 25 mm |
| Outer diameter D | 62 mm |
| Width B | 17 mm |
| Material | GCr15 |
| Seal / shield | 2RS |
| 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 |
| Limiting speed (mechanical) | 7500 rpm |
| Operating temperature | -30 to +110 °C |
| Mass | 240 g |
| Manufacturer designation | SKF 6305-2RSH |
| 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 6305-2RS
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
Contact-sealed execution: greased and sealed for life, no relubrication path. Grease life — not steel fatigue — usually sets the replacement interval; rising running temperature or noise near the end of service is the practical trigger.
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; catalogue load ratings differ by >10% — re-rate the application 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 (2RS 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 (2RS 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 | 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-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 25×62×17 mm envelope per ISO 15; seal variant differs (2RS vs OPEN) — confirm sealing suits the duty. |
| 6305-RSR-NSK | NSK | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 25×62×17 mm envelope per ISO 15; seal variant differs (2RS vs RSR) — confirm sealing suits the duty. |
| 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 (2RS vs ZZ) — confirm sealing suits the duty. |
| 6305-2RS-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-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 25×62×17 mm envelope per ISO 15; seal variant differs (2RS vs OPEN) — confirm sealing suits the duty. |
| 6305-RSR-NTN | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 25×62×17 mm envelope per ISO 15; seal variant differs (2RS vs RSR) — confirm sealing suits the duty. |
| 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 (2RS 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 6305-2RS model number is decoded
6305-2RS is closed by two contacting elastomer lips over a lifetime grease fill; the lips add friction, so the speed ceiling sits below the open execution. 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 contact-seal catalogue number is 6305-2RSH (older text: -2RS1), mapped here from the industry-neutral -2RS spelling.
Typical equipment & failure modes
Common applications
- conveyors and drives
- agricultural equipment
- fans and blowers
- electric motors
Known failure patterns
- seal-lip hardening and loss of pre-grease in sustained high-temperature service
- grease-life expiry in the sealed-for-life cavity (no relubrication path)
- edge loading from shaft deflection or housing misalignment
- rolling-contact fatigue spalling after the rated L10 life is exceeded
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 6305-2RS.
- The 63xx medium series gains rating at 25 mm bore through a 62 mm OD and 17 mm width; the heavier rolling elements also trade away some speed versus a 6205.
- Contact seals add drag and heat: 6305-2RS runs slower and cooler-limited than the open 6305; rubber lips are generally limited to roughly 80–110 °C continuous depending on grease, and C3 clearance is the common hot-duty choice.
- Never wash a sealed 6305-2RS in solvent or press it home via the outer ring; solvent destroys the grease thickener and mounting force through the seal deforms the lip.
- Deep-groove ball bearings tolerate only minutes of misalignment; if the 62 mm housing cannot be aligned, switch to a self-aligning type rather than shimming 6305-2RS.
- 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 contact-sealed version as 6305-2RSH (older printings may read -2RS1); it is shipped pre-greased and its 7500 r/min limiting speed is set by seal-lip drag and grease life versus the open bearing's 24000 r/min thermal reference speed. The single-seal catalogue number is 6305-RSH, used where one shaft side needs external relubrication.
- A one-seal execution 6305-RSH exists for arrangements that lubricate through the open side; fitting 6305-2RSH instead means lifetime grease and no external oil supply — mixing the two in the same shaft can starve the sealed position.
- 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 6305-2RS bearing?
A 6305-2RS 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 contact rubber seals and is normally pre-greased.
How does the 6300 compare with other series at the same 25 mm bore?
The '3' is the medium diameter series: 62×17 mm, 18.5 mm radial section at 25 mm bore, carrying more load than a 6205 but needing a larger housing bore and giving up some speed.
Are 6305 bearings from different brands interchangeable?
For boundary dimensions, yes: every brand's 6305 uses the same ISO 15 envelope (25×62×17 mm). Load ratings, limiting speeds, clearance, precision class and sealing design can differ, so verify those in the supplier catalogue when substituting. Seal suffixes also differ by brand (2RS, DDU, LLU, 2RSL and similar).
What internal clearance does 6305-2RS have?
Unless a clearance suffix says otherwise, 6305-2RS 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 6305 and verify the residual clearance after mounting.
What is the SKF designation and catalogue data for 6305-2RS?
In the SKF Rolling Bearings catalogue this size is listed as 6305-2RSH — two contact elastomer seals over a lifetime grease fill, 25×62×17 mm per ISO 15. Quoted values: C 23.4 kN, C0 11.6 kN, Pu 0.49 kN, limiting speed 7500 r/min, mass 240 g. Brand suffixes (2Z, 2RSH, 2RSL) differ from the industry-neutral spelling 6305-2RS.
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.