4311-ATN9 bearing: complete specifications & equivalents
The 4311-ATN9 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 | 97.5 kN |
| Basic static load rating C0 | 83 kN |
| Fatigue load limit Pu | 3.45 kN |
| Reference speed (thermal) | 9000 rpm |
| Limiting speed (mechanical) | 5000 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 2150 g |
| Manufacturer designation | 4311 ATN9 |
| 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 & 4300-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 4300-series | 12 mm |
| Largest outer diameter in 4300-series | 160 mm |
| Width range across 4300-series | 17–55 mm |
| Bore position in 4300-series (smallest first) | 11 of 14 |
| Bore above smallest 4300-series size | 43 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 62311-2RS | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 55×120×43 mm envelope as SKF 62311-2RS1, but catalogue C/C0 differ (97.5/83 kN vs 71.5/45 kN) — envelope match only after a load check. |
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 4311-ATN9 model number is decoded
4311 ATN9 is a double-row deep-groove ball bearing in the 4300-series: the last two digits encode the bore: 4311 carries code 11 = 55 mm (code × 5). Two complete ball sets share the 55×120×43 mm (2.165×4.724×1.693 in) envelope, giving C 97.5 kN, C0 83 kN and Pu 3.45 kN, with reversing axial capacity a single-row bearing cannot match. ATN9 is the glass-fibre PA66 cage. Limiting speed 5000 r/min, mass 2150 g. The arrangement is open and requires external sealing.
Typical equipment & failure modes
Common applications
- machine tool feed drives
- lifting and hoisting gear
- fans with axial thrust reversals
- industrial wheel arrangements
Known failure patterns
- uneven load sharing between the two raceways when one ring is tilted
- polyamide cage embrittlement after sustained high-temperature service
- fretting corrosion on a creeping shaft or housing seat
- cage damage from running beyond the limiting speed
Selection pitfalls — read before you substitute
- Two deep-groove raceways in 4311-ATN9 share the load but need parallel seats; tilting the 43 mm-wide assembly loads one row heavily and can spall it early.
- The wide 55×120×43 mm envelope is not interchangeable with a single-row 6211 — the housing and shaft shoulders differ, so design the seat for the double-row width from the start.
- Double-row 4311 is open and needs application sealing and lubrication; in dusty drives add external seals rather than expecting the bearing itself to stay clean.
- C 97.5 kN in a 43 mm width is the strength of the double-row design; use it for combined or reversing axial loads rather than pure radial duty where a slimmer single-row bearing would run cooler.
- The ATN9 cage is glass-fibre-reinforced polyamide 66: it is light and quiet but caps continuous service around 100–120 °C in oil/grease — above that use the pressed-steel or machined-cage version of the 55 mm position.
- At 55 mm bore, C3 clearance is the safe choice when interference fits plus temperature rise consume the CN clearance; a hot tight bearing with no residual clearance fails fast.
Frequently asked questions
What are the dimensions of 4311-ATN9?
Double-row 4311 ATN9 measures 55×120×43 mm (2.165×4.724×1.693 in), about 2150 g.
What does ATN9 mean on 4311 ATN9?
A = double-row deep-groove arrangement, TN9 is a glass-fibre-reinforced polyamide 66 cage; it limits continuous temperature to roughly 100–120 °C.
Is 4311-ATN9 interchangeable with a 62-series single-row bearing?
No: although bore matches, OD and width differ and the seat shoulders must suit the wide double-row ring; 55×120×43 mm is its own envelope.
Does 4311-ATN9 run as fast as a single-row bearing?
Somewhat slower: SKF rates it to 5000 r/min; the two cages and wider grease volume generate more drag than a single-row 6211.
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.