2309K bearing: complete specifications & equivalents
The 2309K is a ISO 15 radial bearing sized 45 x 100 x 36 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 45 mm |
| Outer diameter D | 100 mm |
| Width B | 36 mm |
| Seal / shield | open |
| Basic dynamic load rating C | 55 kN |
| Basic static load rating C0 | 16.7 kN |
| Fatigue load limit Pu | 0.71 kN |
| Limiting speed (mechanical) | 5600 rpm |
| Mass | 1200 g |
| Manufacturer designation | 2309SK |
| 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 & 2300-series range
| Bore d | 1.772 in |
|---|---|
| Outer diameter D | 3.937 in |
| Width B | 1.417 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 27.5 mm |
| Smallest bore in 2300-series | 10 mm |
| Largest outer diameter in 2300-series | 215 mm |
| Width range across 2300-series | 17–73 mm |
| Bore position in 2300-series (smallest first) | 10 of 21 |
| Bore above smallest 2300-series size | 35 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 2309K model number is decoded
In the 2300-series (ISO 15 dimension series) the leading digits 23 mark a double-row self-aligning ball bearing and the last two digits encode the bore: 2309 carries bore code 09 = 45 mm. Outside diameter 100 mm and width 36 mm follow the ISO 15 general plan. The K suffix denotes a 1:12 tapered bore for mounting on an adapter sleeve or tapered shaft seat; the cylindrical-bore equivalent is 2309. 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
- agricultural equipment (harvesters, balers)
- industrial fan and blower shafts
- electric motors and generators
- centrifugal pump shafts
Known failure patterns
- contamination wear from dust and dirt ingress through the open arrangement
- lubricant starvation when no regreasing interval is maintained
- edge loading and stress concentration from excessive misalignment beyond the allowable angle
- raceway smearing under marginal lubrication at start-up
Selection pitfalls — read before you substitute
- At a 45 mm bore, a shaft-seat burr or an overtight setscrew can score the thin inner ring of 2309K; check shaft finish and runout (target Ra ≤ 1.6 µm) before pressing it home.
- The 23xx heavy wide-section at 45 mm bore is built for high-load, lower-speed duty; specifying it in a high-rpm application gives excess heat and short grease life — use 12/13 there.
- Tapered-bore 2309K requires a matching adapter sleeve (e.g. H2xx for small bores, H3xx for larger); verify the sleeve bore code matches the 45 mm shaft before ordering.
- The adapter sleeve adds length and a small radial step; check that the housing bore and shaft shoulder clear the sleeve nut and that the withdrawal nut is accessible for future dismounting.
- Self-aligning ball bearings have lower axial load capacity than same-size angular-contact or tapered-roller bearings; verify the axial component is within the Y-factor limits for 2309K.
Frequently asked questions
What are the dimensions of a 2309K self-aligning ball bearing?
A 2309K self-aligning ball bearing has a 45 mm bore, 100 mm outer diameter and 36 mm width, per ISO 15 boundary dimensions. The K suffix indicates a 1:12 tapered bore for adapter-sleeve mounting; the cylindrical-bore version is 2309.
How does the 2309 bore code work?
The last two digits of 2309 are bore code 09, giving 09 × 5 = 45 mm bore. The 100 mm outside diameter and 36 mm width follow the ISO 15 diameter series, not the bore code alone.
What does the K suffix mean on 2309K?
The K suffix denotes a 1:12 tapered bore for mounting with an adapter sleeve. The cylindrical-bore equivalent is 2309. Adapter sleeves are sold separately and must match the bore code.
How does the 2300 compare with other self-aligning series at the same 45 mm bore?
The 23xx is the wide heavy section: 100×36 mm, 27.5 mm radial section at 45 mm bore — the highest-capacity double-row self-aligning option here, aimed at lower-speed, high-load shafts.
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.