NTN 6321-ZZ Bearing — Specifications, Dimensions & Cross-Reference
The NTN 6321-ZZ is a deep groove ball bearing double metal shielded manufactured by NTN. It belongs to the 6300 series and features dimensions of 105 × 225 × 49 mm (bore × OD × width). This bearing has a dynamic load rating of 182,000 N and a static load rating of 153,000 N, making it suitable for heavy-duty applications.
Technical Specifications
| Dimensions | |
|---|---|
| Bore Diameter (d) | 105 mm |
| Outside Diameter (D) | 225 mm |
| Width (B) | 49 mm |
| Weight | 7.200 kg |
| Performance | |
|---|---|
| Dynamic Load Rating (Cr) | 182,000 N |
| Static Load Rating (C₀r) | 153,000 N |
| Limiting Speed (Grease) | 2,800 rpm |
| Limiting Speed (Oil) | 3,400 rpm |
Brand Cross-Reference — 6321-ZZ Equivalents
The following bearings from other manufacturers are interchangeable with the NTN 6321-ZZ. All share identical dimensions (105×225×49mm) and comparable load ratings:
| Brand | Part Number | Dynamic Load (N) | Static Load (N) |
|---|---|---|---|
| NTN | NTN 6321-ZZ ✦ | 182,000 | 153,000 |
| Timken | Timken 6321-ZZ | 182,000 | 153,000 |
| SKF | SKF 6321-ZZ | 182,000 | 153,000 |
| NTN | NTN 6321-ZZ | 182,000 | 153,000 |
| NACHI | NACHI 6321-ZZ | 182,000 | 153,000 |
| KOYO | KOYO 6321-ZZ | 182,000 | 153,000 |
| FAG | FAG 6321-ZZ | 182,000 | 153,000 |
| Timken | Timken 6321-ZZ | 182,000 | 153,000 |
| NSK | NSK 6321-ZZ | 182,000 | 153,000 |
| SKF | SKF 6321-ZZ | 182,000 | 153,000 |
Available Variants
The NTN 6321 base bearing is available in these configurations:
Frequently Asked Questions
What are the dimensions of the NTN 6321-ZZ?
The NTN 6321-ZZ has a bore diameter of 105mm, outside diameter of 225mm, and width of 49mm. It weighs 7.200kg.
What is the load capacity of the NTN 6321-ZZ?
The dynamic load rating (Cr) is 182,000 N and the static load rating (C₀r) is 153,000 N. The maximum recommended speed is 2,800 rpm with grease lubrication or 3,400 rpm with oil lubrication.
What bearings are equivalent to NTN 6321-ZZ?
The 6321-ZZ is manufactured by multiple brands including SKF, NTN, NSK, FAG, Timken, KOYO, and NACHI. All versions share the same 105×225×49mm dimensions and are interchangeable in most applications. See the cross-reference table above for detailed comparisons.