6311 Bearing Dimensions and Cross Reference
6311 = 55 mm bore, 120 mm OD, 29 mm width; deep groove ball bearing, ISO 15.
Verified dimensions
| Bore (d) | 55 mm |
|---|---|
| Outer Diameter (D) | 120 mm |
| Width (B) | 29 mm |
| Type | Deep Groove Ball Bearing |
| Standard | ISO 15 |
In the diagram and table, d is bore diameter, D is outside diameter and B is width.
Sources and evidence
Boundary dimensions are traced to the cited standard. Brand designations and suffixes are checked against the official catalog entry linked for each manufacturer.
Cross-Reference by Brand
| Brand | Part No. | Contact seal | Shield | Boundary dims | Catalog |
|---|---|---|---|---|---|
| SKF | 6311 | 2RSH | 2Z | match | SKF catalog ↗ |
| NSK | 6311 | DDU | ZZ | match | NSK catalog ↗ |
| FAG | 6311 | 2RSR | 2ZR | match | FAG catalog ↗ |
| NTN | 6311 | LLU | ZZ | match | NTN catalog ↗ |
| KOYO | 6311 | 2RS | ZZ | match | KOYO catalog ↗ |
| NACHI | 6311 | 2NSE | ZE | match | NACHI catalog ↗ |
| Timken | 6311 | 2RS | ZZ | match | Timken catalog ↗ |
| INA | 6311 | 2RSR | 2ZR | match | INA catalog ↗ |
Interchange notes
A 6311 candidate must match the complete 55×120×29 mm envelope. Outer diameter alone is not enough: 6213 also has a 120 mm OD, but its 65 mm bore and 23 mm width are different.
For 6311, the contact-seal codes in the verified catalog set include SKF 2RSH, NSK DDU, FAG/INA 2RSR, NTN LLU, KOYO/Timken 2RS and NACHI 2NSE. Shield codes include SKF 2Z, NSK/NTN/KOYO/Timken ZZ, FAG/INA 2ZR and NACHI ZE.
Manufacturer checks before substitution
Confirm load rating, speed limit, internal clearance, precision class, lubrication and application suitability in the official manufacturer catalog for the exact brand and suffix. This page does not supply those values or make an application recommendation. Review the interchange rules before selecting a substitute.
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FAQ
What are the verified 6311 boundary dimensions?
The ISO 15 boundary dimensions are d = 55 mm bore, D = 120 mm outside diameter and B = 29 mm width.
Which sealed 6311 suffixes correspond across brands?
The linked catalogs use different suffix systems. Examples in this table are SKF 6311-2RSH, NSK 6311-DDU, NTN 6311-LLU and FAG/INA 6311-2RSR; confirm the exact suffix in the selected catalog.
Can a 6213 replace a 6311 because both have a 120 mm OD?
No dimensional equivalence follows from OD alone. A 6311 is 55×120×29 mm, while a 6213 is 65×120×23 mm, so the bore and width do not match.
Related sizes
Boundary-dimension cross-reference only. Per the applicable ISO standard (ISO 15 for ball, ISO 355 for tapered), the boundary dimensions are common across brands, so the mounting envelope is interchangeable. This is NOT a drop-in part equivalence. Internal clearance, precision class, seal/shield type (where applicable), cage material and factory lubrication are encoded in brand-specific suffixes and must be matched separately. Always verify against the manufacturer's catalog before substituting.