A bearing number is a compact designation that identifies a bearing’s basic family, bore code, and applicable suffixes. To read bearing numbers correctly, use the complete visible marking rather than treating the numeric portion as the entire part number.
For example, 6204-2RS-C3 contains a basic bearing designation, a seal suffix, and an internal-clearance suffix. NU205ECP includes an NU cylindrical roller bearing pattern, a numeric base, and a manufacturer-specific design suffix. Each segment can affect how the designation is interpreted.
Use the Bearing Number Decoder to break the complete marking into its basic family, bore code, and recognizable suffixes.
Understand the Bearing Number Structure
A bearing designation commonly combines three types of information:
| Part of Designation | Examples | What It Identifies |
|---|---|---|
| Basic family | 62, 63, NU, 302, 222 |
A common bearing family, such as deep-groove ball, cylindrical roller, tapered roller, or spherical roller |
| Bore code | 00, 01, 02, 03, 05, 12 |
A special bore code or a code interpreted using the common multiply-by-five rule |
| Supplementary suffixes | 2RS, ZZ, C3, ECP, TN9 |
Seals, shields, internal clearance, or manufacturer-specific design details |
The basic designation provides the starting point. The bore code identifies the decoded bore size, while suffixes refine the designation. A complete bearing number may include separators such as hyphens, but separators do not make suffixes optional.
Read Bearing Numbers in Order
Use a consistent sequence to avoid overlooking part of the marking.
- Start with the complete designation printed on the bearing, package, or catalog entry.
- Identify the basic family pattern, such as
62,63,NU,302, or222. - Read the bore code within the basic designation.
- Check for seal or shield suffixes, including
2RS,RS,ZZ,2Z,Z, or2RU. - Check for an internal-clearance suffix, such as
C1,C2,C3,C4,C5, orCN. - Preserve remaining design suffixes, including
ECP,EC,E,M,TN9, orJ. - Verify the exact manufacturer catalog entry when the designation will be used for purchasing, maintenance, replacement, or safety-related decisions.
When using the decoder, enter every visible character, including prefixes, digits, letters, suffixes, and separators. Review the decoded summary first, then use the segment breakdown to identify which portion of the code supports each reported result.
Identify the Basic Bearing Family
The opening portion of a designation often identifies the bearing family. Common patterns recognized by the decoder include the examples below.
| Basic Family Example | General Family Reported |
|---|---|
62 |
Deep-groove ball bearing |
63 |
Deep-groove ball bearing |
NU |
Cylindrical roller bearing pattern |
302 |
Tapered roller bearing pattern |
222 |
Spherical roller bearing pattern |
The family identifies a general bearing type, but it does not by itself establish every dimension or feature. A complete catalog designation is still needed to verify details relevant to selection or replacement.
Metric tapered roller bearings and inch-design tapered roller bearings use separate designation systems. Check the exact manufacturer catalog entry rather than treating a number pattern as proof of a direct equivalent.
Decode the Bore Code
The bore code is the part interpreted as the bearing bore size. Common examples include special codes such as 00, 01, 02, and 03, along with codes such as 05 and 12 that can use the common multiply-by-five rule.
For a focused explanation of code patterns and the information that bore-code decoding does not establish, see Bearing Bore Code and Dimensions.
The decoder reports whether it has recognized a special bore-code pattern or applied the common rule. That output identifies the decoded bore size, but bore-code parsing alone does not determine:
- Outside diameter
- Width
- Cage material
- Lubrication
- Fit
- Load rating
- Interchangeability
A bearing number should not be reduced to bore size alone. The family and all supplementary markings remain part of the designation.
Read Seals, Shields, and Clearance Suffixes
Suffixes can change the meaning of an otherwise familiar base number. Keep them attached to the bearing designation when entering a part number into a decoder, catalog search, procurement system, or maintenance record.
| Suffix Category | Examples | Decoder Output |
|---|---|---|
| Seal or shield | 2RS, RS, ZZ, 2Z, Z, 2RU |
Recognized seal or shield wording, subject to manufacturer-specific interpretation |
| Internal clearance | C1, C2, C3, C4, C5, CN |
Recognized clearance-suffix wording, with catalog verification required |
| Design suffix | ECP, EC, E, M, TN9, J |
Preserved as a design suffix, generally with a manufacturer-specific warning |
For recognized seal, shield, and clearance categories, see Bearing Seal, Shield, and Clearance Suffixes.
Seal and shield markings may be recognizable across common designation systems, but their exact meaning can vary by manufacturer. The same caution applies to design suffixes: a decoder can preserve and flag a suffix without expanding it into a universal feature claim.
Internal-clearance suffixes are associated with recognized clearance wording, including C3 and CN. The exact catalog entry remains the appropriate source for final confirmation. ISO rolling-bearing references, including ISO 5753-1 for radial internal clearance, are among the references associated with these suffix categories.
Bearing Number Examples
6206-2RS-C3
6206-2RS-C3 can be read as:
62: Deep-groove ball bearing series06: Bore code interpreted as a 30 mm bore2RS: Two rubber sealsC3: C3 internal clearance
The suffixes are part of the complete designation. Reading only 6206 omits the seal and clearance information.
6312-ZZ
6312-ZZ can be read as:
63: Deep-groove ball bearing series12: Bore code interpreted as a 60 mm boreZZ: Two metal shields
The base number identifies the series and bore code, while ZZ adds the recognized shield designation.
NU205ECP
NU205ECP can be read as:
NU: Cylindrical roller bearing pattern05: Bore code interpreted as a 25 mm boreECP: Preserved design suffix
ECP should not be converted into a universal claim about materials, construction, or performance. Verify its exact meaning in the applicable manufacturer catalog.
Use Decoded Results Correctly
The decoded result is a structured starting point, not an official catalog lookup. Confirm that the summary identifies a bearing family and bore size, then review the segment breakdown to see which characters support each reported result.
For parser boundaries and catalog-verification limits, see Bearing Number Parser Limits.
Read bearing numbers as complete designations: identify the family and bore code, retain seal, shield, clearance, and design suffixes, then verify the exact manufacturer catalog entry before using the result for purchasing, maintenance, replacement, or safety-related decisions.