1305 bearing: complete specifications & equivalents
The 1305 is a ISO 15 radial bearing sized 25 x 62 x 17 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 25 mm |
| Outer diameter D | 62 mm |
| Width B | 17 mm |
| Seal / shield | open |
| Basic dynamic load rating C | 18.2 kN |
| Basic static load rating C0 | 5 kN |
| Fatigue load limit Pu | 0.15 kN |
| Limiting speed (mechanical) | 10000 rpm |
| Mass | 261 g |
| Manufacturer designation | 1305S |
| Standard | ISO 15 |
| Catalog version | CAT. No. 2203-3/E 2024 |
| Last verified | 2026-09-25 |
Source: catalog reference (CAT. No. 2203-3/E 2024) · extracted 2026-09-25
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (CAT. No. 2203-3/E 2024); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.
Dimensions in inches & 1300-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 1300-series | 10 mm |
| Largest outer diameter in 1300-series | 240 mm |
| Width range across 1300-series | 11–50 mm |
| Bore position in 1300-series (smallest first) | 6 of 23 |
| Bore above smallest 1300-series size | 15 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 1305 model number is decoded
In the 1300-series (ISO 15 dimension series) the leading digits 13 mark a double-row self-aligning ball bearing and the last two digits encode the bore: 1305 carries bore code 05 = 25 mm. Outside diameter 62 mm and width 17 mm follow the ISO 15 general plan. The cylindrical bore fits directly on a machined shaft seat; a tapered-bore K variant is available for adapter-sleeve mounting. Two rows of balls run on a common sphered outer raceway, allowing the inner ring to pivot and compensate for shaft deflection or housing misalignment.
Typical equipment & failure modes
Common applications
- centrifugal pump shafts
- small gearbox input/output shafts
- conveyor roller and pulley shafts
- agricultural equipment (harvesters, balers)
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- rolling-contact fatigue spalling after the rated L10 life is exceeded
- cage wear or fracture from sustained vibration or shock loading
Selection pitfalls — read before you substitute
- At a 25 mm bore, a shaft-seat burr or an overtight setscrew can score the thin inner ring of 1305; check shaft finish and runout (target Ra ≤ 1.6 µm) before pressing it home.
- The 13xx medium section at 25 mm bore gains rating through a larger 62 mm OD and 17 mm width; verify the housing accepts the larger envelope before substituting for a 1205.
- The open 1305 has no lubricant retention: grease escapes and contaminants migrate straight into the 25×62×17 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Open bearings tolerate the highest speeds in the 1300-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 1305 units.
- Shaft and housing fillets must clear the bearing chamfer so the 17 mm-wide ring seats square; provide an undercut or withdrawal groove instead of relying on an oversized radius.
Frequently asked questions
What are the dimensions of a 1305 self-aligning ball bearing?
A 1305 self-aligning ball bearing has a 25 mm bore, 62 mm outer diameter and 17 mm width, per ISO 15 boundary dimensions. This is the cylindrical-bore version; a tapered-bore K variant is available for adapter-sleeve mounting.
How does the 1305 bore code work?
The last two digits of 1305 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 open suffix mean on 1305?
A bare 1305 designation means open: no shields or seals, normal CN radial clearance and P0 normal tolerance unless further suffixes are ordered. The application must supply and retain the lubrication.
How does the 1300 compare with other self-aligning series at the same 25 mm bore?
The 13xx is the medium section: 62×17 mm, 18.5 mm radial section at 25 mm bore, carrying more load than a 1205 but needing a larger housing bore.
Reviewed & verified by the MPN Base engineering desk against source catalog CAT. No. 2203-3/E 2024 on 2026-09-25. Read our editorial & correction policy.