QJ311 Bearing — Cross-Reference & Equivalents
The QJ311 is a four-point contact ball bearing with ISO 15 boundary dimensions 55×120×29 mm. The table below lists how 8 major brands designate it, with catalog links and interchange notes.
Replacing a QJ311? The cross-reference table below gives the equivalent part number for every major brand — but read the interchange rules first: an identical size is not always a safe swap.
Specifications
| Bore (d) | 55 mm |
|---|---|
| Outer Diameter (D) | 120 mm |
| Width (B) | 29 mm |
| Type | Four-Point Contact Ball Bearing |
| Standard | ISO 15 |
Cross-Reference by Brand
| Brand | Part No. | Boundary dims | Catalog |
|---|---|---|---|
| SKF | QJ311 | match | SKF catalog ↗ |
| NSK | QJ311 | match | NSK catalog ↗ |
| FAG | QJ311 | match | FAG catalog ↗ |
| NTN | QJ311 | match | NTN catalog ↗ |
| KOYO | QJ311 | match | KOYO catalog ↗ |
| NACHI | QJ311 | match | NACHI catalog ↗ |
| Timken | QJ311 | match | Timken catalog ↗ |
| INA | QJ311 | match | INA catalog ↗ |
Interchange notes
All brands build this designation to the same ISO 15 boundary dimensions (d, D, B), so the mounting envelope is interchangeable. For four-point contact ball bearings, matching dimensions is not enough: (1) A single bearing carries axial load in BOTH directions (its split inner ring contacts the balls at four points), so it replaces a back-to-back pair as a locating bearing — it is NOT interchangeable with a deep groove or standard single-row angular contact bearing of the same size. (2) The inner ring is split into two halves that are matched at manufacture and must stay together. (3) It is built mainly for axial/combined load with limited pure-radial capacity, and is typically paired with a separate radial bearing (e.g. an NU) that takes the radial load. (4) Match cage (e.g. MA machined brass), locating feature (N2 slots) and clearance/preload class. Load ratings (dynamic Cr, static C0r) are intentionally NOT listed here: they vary by brand and internal design and are a safety-critical selection parameter — read them directly from the manufacturer catalog linked in the table above.
Where to buy a QJ311
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FAQ
What bearings are equivalent to a QJ311?
The QJ311 is built to ISO 15 boundary dimensions 55×120×29 mm by SKF, NSK, FAG, NTN, KOYO, NACHI, Timken, INA. All share the same mounting envelope; match clearance, precision class and (where applicable) seal suffix before substituting.
What are the dimensions of a QJ311 bearing?
Bore 55 mm, outer diameter 120 mm, B 29 mm (ISO 15).
Can a QJ311 replace a deep groove or angular contact bearing?
No. The QJ311 shares its 55×120×29 mm envelope, but a four-point contact bearing takes axial load in both directions via a split inner ring — it works as a locating bearing replacing a back-to-back pair, not as a deep groove or single-row angular contact bearing. It has limited pure radial capacity and is usually paired with a separate radial bearing. Match cage and clearance/preload class.
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.