You can learn a lot about a bearings just from its part number.
A typical bearings is the 6203ZZ bearings. This part number can be divided into its components:
62203ZZ which means:
- Suffix
- Bore
- Series
- Type Code
Suffix (62203ZZ)
The last letters indicate something’s special about the bearings, through the suffix. For example:
| Z | Shield fitted at one side of bearings (P,D) | |
| ZZ | Shield fitted at both side of bearings (PP,DD) | |
| RS | Synthetic rubber seal fitted at one side of bearings (PS,PG) | |
| 2RS | Synthetic rubber seal fitted at both sides of bearings (PPS,PPG) | |
| LS | Labyrinth seal on one side | |
| 2LS | Labyrinth seal on both side | |
| K | Tapered bore , taper 1:12 on diameter[T (prefix ),N] | |
| K30 | Tapered bore , taper1:30 on diameter | |
| N | Snap ring groove in outer ring (K,G) | |
| NR | Snap ring groove in outer ring , with snap ring (KR ,GR) | |
| ZN | Shield at one side and snap ring groove ring at the other (KP,GD) | |
| ZNR | As for ZN , but including snap ring | |
| N2 | Two diametrically opposed slots at one outside corner of outer ring | |
| G | Single row angular contact ball bearing with faces adjusted so that any two bearings | |
| Can be mounted in pairs, either in tandem, back to back or face to face. | ||
| W20 | Double row spherical roller bearings with three lubrication holes in outer ring. | |
| W33 | Double spherical roller bearings with groove and three lubrication holes in outer ring | |
| E | Latest cage design | |
| J | Pressed cage made of steel | |
| M | Solid cage of bronze or brass | |
| T | Solid cage made of textile (fabric reinforced phenolic resin) | |
| TN | Solid cage made of polyamide | |
| Other bearings features | ||
| C0 | Normal internal clearance (symbol not indicated) | |
| C2 | Less than normal internal clearance. | |
| C3 | More than normal internal clearance. | |
| C4/C5 | High play bearings (for vibrations) | |
| P0 | Standard accuracy (symbol not indicated) | |
| P6 | Accuracy of ISO class 6 | |
| P5 | Accuracy of ISO class 5 (greater than P6) | |
| P4 | Accuracy of ISO class 4 (greater than P5) | |
Bore (62203ZZ)
The last two digits (if there is a suffix, then the digits before it), give details of the bore of the bearings.
For the last two digits being 00, 01, 02, or 03 following are the bore sizes.
- 00 10 mm
- 01 12 mm
- 02 15 mm
- 03 17 mm
For digits beyond 03, the bore size is simply five times the last two digits together.
e.g., if the last two digits are 06 (as in 6206), then the bore size is 06×5=30mm.
If there is no fourth digit – for example, a 608 bearings, a common roller skate bearing – then the size is the last digit in mm. i.e. bore size bearings 608 is 8 mm
Series (62203ZZ)
The digit before the indicating number (the third digit from end), represents the series, which reflects the robustness of the bearings. The series are, from lightest to heaviest:
8 Extra thin section (e.g.6806)
9 Very thin section (e.g.6906)
0 Extra light (e.g.6006)
1 Extra light thrust (e.g.51106)
2 Light (e.g.6206)
3 Medium (e.g.6306)
4 Heavy (e.g.6406)
Type Code (62203ZZ)
The type code indicates the type of bearings. Each manufacturer uses their own numbers. They could be single or double digits or alphabets.