2311-K bearing: complete specifications & equivalents
The 2311-K is a ISO 15 radial bearing sized 55 x 120 x 43 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 55 mm |
| Outer diameter D | 120 mm |
| Width B | 43 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 76.1 kN |
| Basic static load rating C0 | 24 kN |
| Fatigue load limit Pu | 1.25 kN |
| Reference speed (thermal) | 11000 rpm |
| Limiting speed (mechanical) | 7500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2100 g |
| Manufacturer designation | 2311 K |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-27
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 & 2300-series range
| Bore d | 2.165 in |
|---|---|
| Outer diameter D | 4.724 in |
| Width B | 1.693 in |
| ISO bore code | 11 |
| Radial section height (D−d)/2 | 32.5 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) | 12 of 21 |
| Bore above smallest 2300-series size | 45 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 2311 | 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. |
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 2311-K model number is decoded
The 23xx series is the wide medium-section self-aligning ball bearing (ISO dimension series 23). the last two digits encode the bore: 2311 carries code 11 = 55 mm (code × 5). Envelope 55×120×43 mm (2.165×4.724×1.693 in) with a 32.5 mm radial section height, C 76.1 kN, C0 24 kN and Pu 1.25 kN. The open 2311 K carries no shields or seals and relies on application lubrication and external sealing. The suffix identifies the glass-fibre-reinforced polyamide 66 cage execution. The K suffix marks a 1:12 tapered bore for direct mounting on a tapered shaft or with an adapter sleeve. Reference (thermal) speed 11000 r/min, limiting speed 7500 r/min, catalogue mass 2100 g.
Typical equipment & failure modes
Common applications
- material-handling equipment
- industrial electric motors
- conveyor drum and pulley shafts
- agricultural gearboxes
Known failure patterns
- contamination wear when the open arrangement is used without adequate external sealing
- lubricant starvation where no regreasing interval is maintained
- adapter-sleeve fretting when the sleeve is not locked against the shaft shoulder
- incorrect sleeve tightening that leaves the tapered bore loose or over-expanded, changing internal clearance
- raceway smearing under marginal lubrication at start-up
- electrical pitting in VFD-driven motors without shaft grounding
Selection pitfalls — read before you substitute
- Catalogue ratings for 2311-K (C 76.1 kN, C0 24 kN) are SKF figures from PUB BU/P1 17000; geometry revisions can change ratings without changing the designation, so keep the catalogue edition with the specification.
- Catalogue ratings for 2311-K (C 76.1 kN, C0 24 kN) are SKF figures from PUB BU/P1 17000; geometry revisions can change ratings without changing the designation, so keep the catalogue edition with the specification.
- The K suffix means a 1:12 tapered bore: 2311-K is not a drop-in for the straight-bore version — it needs a tapered shaft or an H-series adapter sleeve.
- The suffix on 2311-K denotes a glass-fibre-reinforced polyamide 66 cage: quiet and light at the 7500 r/min limiting speed, but it softens above roughly 120 °C — check the oil temperature in hot drives.
- The spherical outer raceway lets 2311-K tolerate shaft deflection, but it does not increase thrust capacity — combined loads still need an angular-contact or deep-groove bearing.
- Fillet radii must clear the 2311-K chamfer so the 43 mm-wide ring seats square; an oversized shaft radius creates point contact on the ring face.
Frequently asked questions
What are the dimensions of 2311-K?
SKF 2311 K measures 55 mm bore × 120 mm OD × 43 mm width (2.165 × 4.724 × 1.693 in), mass about 2100 g. It is open, with no shields or seals.
How does the bore code in 2311 work?
The final two digits of 2311 are bore code 11, multiplied by 5 to give 55 mm.
How heavy is 2311-K?
Catalogue mass is 2100 g for 2311 K; seal and cage executions of the same envelope differ by a few grams.
What load can 2311-K take?
Catalogue values for 2311 K: dynamic C 76.1 kN, static C0 24 kN, fatigue limit Pu 1.25 kN. Use C in life calculation and C0 for static checks at 55 mm bore.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-27. Read our editorial & correction policy.