1211-EKTN9 bearing: complete specifications & equivalents
The 1211-EKTN9 is a ISO 15 radial bearing sized 55 x 100 x 21 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 | 100 mm |
| Width B | 21 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | polymer (PA66 glass-fibre reinforced) |
| Basic dynamic load rating C | 27.6 kN |
| Basic static load rating C0 | 10.6 kN |
| Fatigue load limit Pu | 0.54 kN |
| Reference speed (thermal) | 14000 rpm |
| Limiting speed (mechanical) | 9000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 710 g |
| Manufacturer designation | 1211 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 & 1200-series range
| Bore d | 2.165 in |
|---|---|
| Outer diameter D | 3.937 in |
| Width B | 0.827 in |
| ISO bore code | 11 |
| Radial section height (D−d)/2 | 22.5 mm |
| Smallest bore in 1200-series | 6 mm |
| Largest outer diameter in 1200-series | 230 mm |
| Width range across 1200-series | 6–154 mm |
| Bore position in 1200-series (smallest first) | 17 of 32 |
| Bore above smallest 1200-series size | 49 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 1211 | 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. |
| 1211-ETN9 | SKF | full Dimensions and internal design equivalent — standard interchange. | Same 55×100×21 mm envelope with catalogue ratings within 10 %; 1211 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 1211-EKTN9 model number is decoded
The 12xx series is the light/normal-section self-aligning ball bearing (ISO dimension series 02). the last two digits encode the bore: 1211 carries code 11 = 55 mm (code × 5). Envelope 55×100×21 mm (2.165×3.937×0.827 in) with a 22.5 mm radial section height, C 27.6 kN, C0 10.6 kN and Pu 0.54 kN. The open 1211 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 14000 r/min, limiting speed 9000 r/min, catalogue mass 710 g.
Typical equipment & failure modes
Common applications
- textile machinery drives
- industrial fans and blowers
- woodworking machinery
- pump shafts with mild misalignment
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 1211-EKTN9 (C 27.6 kN, C0 10.6 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 spherical outer raceway lets 1211-EKTN9 tolerate shaft deflection, but it does not increase thrust capacity — combined loads still need an angular-contact or deep-groove bearing.
- Tighten the adapter sleeve to the SKF-recommended starting clearance, not to feel — an over-tightened sleeve expands the inner ring and removes all internal clearance.
- The EKTN9 suffix on 1211-EKTN9 denotes a glass-fibre-reinforced polyamide 66 cage: quiet and light at the 9000 r/min limiting speed, but it softens above roughly 120 °C — check the oil temperature in hot drives.
- Catalogue ratings for 1211-EKTN9 (C 27.6 kN, C0 10.6 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.
- Mount 1211-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.
Frequently asked questions
What are the dimensions of 1211-EKTN9?
SKF 1211 EKTN9 measures 55 mm bore × 100 mm OD × 21 mm width (2.165 × 3.937 × 0.827 in), mass about 710 g. It is open, with no shields or seals.
How does the bore code in 1211 work?
The final two digits of 1211 are bore code 11, multiplied by 5 to give 55 mm.
Can 1211-EKTN9 take axial load?
A self-aligning ball bearing can carry some axial load in addition to radial load, but its axial capacity is lower than an angular-contact bearing of the same envelope. Use it where misalignment, not thrust, is the main requirement.
Which fits should I use for 1211-EKTN9?
With a rotating inner ring use roughly k5 on the shaft and H7 in the 100 mm housing; reverse the interference if the outer ring rotates.
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.