Tapered Roller Bearing Numbers Explained: 32206, 30303C and ISO 355
Tapered roller bearings support combined radial and axial loads. Their inner and outer rings are separable, which supports installation and adjustment. Metric tapered roller bearing designations typically begin with the digit 3.
Metric designation structure
| Part | Meaning | Example |
|---|---|---|
| First digit | 3 = tapered roller bearing | 3 |
| Following digits | Width and diameter series | 22 |
| Bore code | For codes from 04 upward, bore = code × 5 mm | 06 = 30 mm |
Example: 32206
3 identifies a tapered roller bearing. 22 is the size series. 06 gives a 30 mm bore (06 × 5 mm).
Example: 30303C
3 identifies a tapered roller bearing. 03 is the size series. 03 denotes a 17 mm bore. The C suffix identifies a medium contact-angle design, approximately 20°.
Contact-angle and design suffixes
- C: approximately 20° contact angle.
- D: approximately 28°30′ contact angle.
- B: large contact-angle design, typically 25° to 29°.
- J: conforms to ISO grouping provisions.
- HR: high-load tapered roller bearing prefix.
ISO 355 and inch-series references
In ISO 355 references, the series code comprises a digit and two letters followed by a three-digit bore dimension. Some SKF basic designations begin with T, such as T2ED 045. Inch-series tapered roller bearing numbers commonly include a prefix that indicates duty class, an angle code, a basic series number, a component number and any special suffix.
FAQ
Can a tapered roller bearing carry axial load in both directions?
A single tapered roller bearing primarily carries axial load in one direction. Arrangements such as paired bearings are used when axial load must be accommodated in both directions.
Can the cone and cup be mixed between brands?
Do not assume interchangeability. Confirm dimensions, contact geometry, clearance and manufacturer's compatibility data.
View HX tapered roller bearing models for combined-load applications.