2318 bearing: complete specifications & equivalents
The 2318 is a ISO 15 radial bearing sized 90 x 190 x 64 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 90 mm |
| Outer diameter D | 190 mm |
| Width B | 64 mm |
| Seal / shield | open |
| Basic dynamic load rating C | 154 kN |
| Basic static load rating C0 | 57.5 kN |
| Fatigue load limit Pu | 2.4 kN |
| Limiting speed (mechanical) | 2800 rpm |
| Mass | 7750 g |
| Manufacturer designation | 2318S |
| 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 | 3.543 in |
|---|---|
| Outer diameter D | 7.48 in |
| Width B | 2.52 in |
| ISO bore code | 18 |
| Radial section height (D−d)/2 | 50 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) | 19 of 21 |
| Bore above smallest 2300-series size | 80 mm |
Cross references & equivalents
No verified interchange data yet. Send an inquiry and our team will confirm equivalents manually.
How the 2318 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: 2318 carries bore code 18 = 90 mm. Outside diameter 190 mm and width 64 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
- heavy industrial drive shafts
- large gearbox and reducer shafts
- industrial fan and blower rotors
- hoist, winch and crane drums
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
- Mount this 90 mm bore bearing by heating the inner ring (induction heater, max 120 °C) — never drive it home through the outer ring or balls, that brinells the raceways.
- The 23xx heavy wide-section at 90 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.
- The open 2318 has no lubricant retention: grease escapes and contaminants migrate straight into the 90×190×64 mm raceway, so specify a sealed arrangement for dusty or washdown duty.
- Open bearings tolerate the highest speeds in the 2300-series but need a defined regreasing interval; run-to-failure lubrication is the dominant cause of early failure in open 2318 units.
- Do not use a self-aligning ball bearing where high radial rigidity is required — the sphered outer raceway allows more radial movement than a deep-groove or cylindrical roller bearing.
Frequently asked questions
What are the dimensions of a 2318 self-aligning ball bearing?
A 2318 self-aligning ball bearing has a 90 mm bore, 190 mm outer diameter and 64 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 2318 bore code work?
The last two digits of 2318 are bore code 18, giving 18 × 5 = 90 mm bore. The 190 mm outside diameter and 64 mm width follow the ISO 15 diameter series, not the bore code alone.
What does the open suffix mean on 2318?
A bare 2318 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 2300 compare with other self-aligning series at the same 90 mm bore?
The 23xx is the wide heavy section: 190×64 mm, 50.0 mm radial section at 90 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.