1311-EKTN9 bearing: complete specifications & equivalents
The 1311-EKTN9 is a ISO 15 radial bearing sized 55 x 120 x 29 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 | 29 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 50.7 kN |
| Basic static load rating C0 | 18 kN |
| Fatigue load limit Pu | 0.92 kN |
| Reference speed (thermal) | 11000 rpm |
| Limiting speed (mechanical) | 7500 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 1600 g |
| Manufacturer designation | 1311 EKTN9 |
| 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 & 1300-series range
| Bore d | 2.165 in |
|---|---|
| Outer diameter D | 4.724 in |
| Width B | 1.142 in |
| ISO bore code | 11 |
| Radial section height (D−d)/2 | 32.5 mm |
| Smallest bore in 1300-series | 5 mm |
| Largest outer diameter in 1300-series | 320 mm |
| Width range across 1300-series | 6–74 mm |
| Bore position in 1300-series (smallest first) | 13 of 29 |
| Bore above smallest 1300-series size | 50 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 1311 | 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. |
| 1311-ETN9 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 55×120×29 mm envelope with catalogue ratings within 10 %; 1311 ETN9 is the glass-fibre PA66 cage, open arrangement execution of this size — boundary dimensions interchangeable, only the seal/cage/bore execution differs. |
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 1311-EKTN9 model number is decoded
The 13xx series is the medium/normal-section self-aligning ball bearing (ISO dimension series 03). the last two digits encode the bore: 1311 carries code 11 = 55 mm (code × 5). Envelope 55×120×29 mm (2.165×4.724×1.142 in) with a 32.5 mm radial section height, C 50.7 kN, C0 18 kN and Pu 0.92 kN. The open 1311 EKTN9 carries no shields or seals and relies on application lubrication and external sealing. The EKTN9 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 1600 g.
Typical equipment & failure modes
Common applications
- industrial fans and blowers
- woodworking machinery
- pump shafts with mild misalignment
- material-handling equipment
Known failure patterns
- lubricant starvation where no regreasing interval is maintained
- contamination wear when the open arrangement is used without adequate external sealing
- incorrect sleeve tightening that leaves the tapered bore loose or over-expanded, changing internal clearance
- adapter-sleeve fretting when the sleeve is not locked against the shaft shoulder
- cage damage from running beyond the limiting speed
- raceway smearing under marginal lubrication at start-up
Selection pitfalls — read before you substitute
- Assign interference to the rotating ring: on a 55 mm rotating shaft use a k5 seat with an H7 housing; reverse the logic if the outer ring rotates.
- Fillet radii must clear the 1311-EKTN9 chamfer so the 29 mm-wide ring seats square; an oversized shaft radius creates point contact on the ring face.
- On a sleeve-mounted 1311-EKTN9, lock the sleeve against the shaft shoulder; a loose sleeve creeps and frets both the shaft and the bore.
- The EKTN9 suffix on 1311-EKTN9 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.
- Mount 1311-EKTN9 by heating the inner ring (max 120 °C) on a cylindrical bore — driving it home through the outer ring or balls brinells the raceways.
- The fatigue load limit is 0.92 kN; it feeds the equivalent-mean-load check, not the basic life calculation — do not substitute one for the other.
Frequently asked questions
What are the dimensions of 1311-EKTN9?
SKF 1311 EKTN9 measures 55 mm bore × 120 mm OD × 29 mm width (2.165 × 4.724 × 1.142 in), mass about 1600 g. It is open, with no shields or seals.
How does the bore code in 1311 work?
The final two digits of 1311 are bore code 11, multiplied by 5 to give 55 mm.
Which fits should I use for 1311-EKTN9?
With a rotating inner ring use roughly k5 on the shaft and H7 in the 120 mm housing; reverse the interference if the outer ring rotates.
How heavy is 1311-EKTN9?
Catalogue mass is 1600 g for 1311 EKTN9; seal and cage executions of the same envelope differ by a few grams.
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.