21304CA is a spherical roller designation documented on BearingIndex from 1 manufacturer publication. The published boundary dimensions are 20 × 52 × 15 mm. The designation ends in bore code 04, which resolves to a 20 mm bore under ISO 15 and matches what the manufacturers published. Every value below comes from that manufacturer’s own published material, with the date it was recorded.
A dash means that manufacturer did not publish the value. Dimensions every source agrees on are shown above rather than repeated per row.
| Figure | How it is obtained | Result |
|---|---|---|
| Radial section height | (D − d) / 2 | 16 mm |
| Mean diameter dm | (D + d) / 2 | 36 mm |
Arithmetic on the figures above — not a bearing life calculation for your load case.
Precision and special bearings
The public product range includes precision and special bearings. Model-level dimensions and supporting technical documents have not yet been added to this directory.
87 designations documented here · 1 reviewed evidence record · source recorded 2026-09-21
Precision class · Internal clearance · Sealing · Material · Cage material · Z class · V class · Application · Dynamic load rating · Static load rating · Limiting speed · Lubrication · Operating temperature · Precision standard · Ring material · Rolling element material · Limiting speed — grease · Limiting speed — oil · Noise / vibration test method · Manufacturer series · Manufacturer suffix · Ball count · Ball diameter · Reference mass.
Ask the manufacturer for these when you enquire.
| Designation | Bearing family | Works |
|---|---|---|
| 21304CTN1 | Spherical roller | 1 |
| 30304 | Tapered roller | 1 |
| 6304 | Deep groove ball | 3 |
| 6304-2RZ | Deep groove ball | 1 |
| 6304E | Deep groove ball | 1 |
| 6304ZZ/2RS | Deep groove ball | 1 |
| 760304-TN | Angular contact | 1 |
| S6304ZZ/2RS | Deep groove ball | 1 |
Same envelope, but sealing, internal design, clearance and load capability differ — not interchangeable by default.
| Designation | Envelope d × D × B (mm) | Bearing family | Works |
|---|---|---|---|
| 21304CTN1 | 20 × 52 × 15 | Spherical roller | 1 |
| 21305CA | 25 × 62 × 17 | Spherical roller | 1 |
| 21305CTN1 | 25 × 62 × 17 | Spherical roller | 1 |
| 21306CA | 30 × 72 × 19 | Spherical roller | 1 |
| 21306CTN1 | 30 × 72 × 19 | Spherical roller | 1 |
| 21307CA | 35 × 80 × 21 | Spherical roller | 1 |
| 21307CTN1 | 35 × 80 × 21 | Spherical roller | 1 |
| 21308CA | 40 × 90 × 23 | Spherical roller | 1 |
| 21308CC | 40 × 90 × 23 | Spherical roller | 1 |
Each envelope shown is that designation’s own published size.
Tick the works you want above, then send one enquiry — each manufacturer answers you separately and cannot see the others.
Figures on this page are each manufacturer’s own published material, recorded on the dates shown. How we check sources →
