Bearing Identification6 min read
How to Read & Decode a Bearing Part Number
Learn the universal ISO bearing designation system. Decode prefix codes, bearing type identifiers, series numbers, bore codes, and critical suffix codes (2RS, ZZ, C3, P6, M, NR).
1. Anatomy of an ISO Bearing Part Number Standard metric rolling bearings follow a standardized alphanumeric designation structure:
``` [Prefix] + [Type Identifier] + [Series Code] + [Bore Code] + [Internal Design] + [Seals/Shields] + [Clearance/Precision] Example: 6204-2RS-C3 ```
---
2. Breaking Down the Code: 6204-2RS-C3 - **`6`** = **Bearing Type**: Deep Groove Ball Bearing (1 = Self-aligning ball, 2 = Spherical roller, 3 = Double row angular contact / Tapered roller, 5 = Thrust ball, 7 = Single row angular contact, N = Cylindrical roller). - **`2`** = **Dimensional Series**: Light Duty Series (8 = Extremely thin, 9 = Thin, 0 = Extra light, 2 = Light, 3 = Medium, 4 = Heavy). - **`04`** = **Bore Code**: Multiplied by 5 to calculate bore diameter in millimeters (for codes 04 and above): - `00` = 10 mm - `01` = 12 mm - `02` = 15 mm - `03` = 17 mm - `04` = 20 mm ($04 imes 5 = 20$) - `05` = 25 mm ($05 imes 5 = 25$) - `10` = 50 mm ($10 imes 5 = 50$) - **`-2RS`** = **Closure Suffix**: Dual NBR rubber contact seals. - **`-C3`** = **Clearance Suffix**: Radial internal clearance greater than Normal.
---
3. Common Suffix Glossary - **`Z` / `ZZ`**: Single / Double pressed steel metal shield - **`RS` / `2RS`**: Single / Double rubber contact seal - **`RZ` / `2RZ`**: Single / Double non-contact rubber seal - **`C2 / C3 / C4 / C5`**: Internal radial clearance class - **`P0 / P6 / P5 / P4`**: Precision tolerance class - **`M / MA / MB`**: Machined solid brass cage - **`TN9 / TVH`**: Glass fiber reinforced Polyamide 66 cage - **`NR`**: Snap ring groove in outer ring with snap ring fitted
Need Help Specifying Bearings for Your Machinery?
Connect with Amman Spares for technical confirmation, brand options, and quotation.