Every ball bearing has a code stamped on its shield or seal, such as 608ZZ or 6202RS. That code tells you the bearing's size and how it is protected from dust. If you can read the code, you can order the right replacement without taking measurements.
The numbers: size
The number part of the code (608, 626, 6202) stands for a set size: the bore (the hole in the middle), the outer diameter and the width, all in millimetres. For example, a 608 bearing is 8mm bore x 22mm outer diameter x 7mm wide. Two bearings with the same number are the same size, whichever brand made them.
The letters: shields and seals
- Z: one metal shield on one side.
- ZZ or 2Z: metal shields on both sides. Good for general use where dust is the main concern.
- RS: a rubber seal on one side. 2RS means rubber seals on both sides, which keep out water and fine dust better than metal shields.
- F at the start (for example F623ZZ): a flanged bearing with a lip on the outer ring.
Bearing size chart
These are the sizes we stock, with links to each product.
| Code | Bore x outer x width | Pack |
|---|---|---|
| F623ZZ (flanged) | 3 x 10 x 4mm | 10 pack |
| 694Z | 4 x 11 x 4mm | 4 pack |
| 624ZZ | 4 x 13 x 5mm | 10 pack |
| 605ZZ | 5 x 14 x 5mm | 4 pack |
| 635Z | 5 x 19 x 6mm | 10 pack |
| 696ZZ | 6 x 15 x 5mm | 4 pack |
| 626ZZ | 6 x 19 x 6mm | 4 pack |
| 607ZZ | 7 x 19 x 6mm | 10 pack |
| 627Z | 7 x 22 x 7mm | 10 pack |
| 698Z | 8 x 19 x 6mm | 4 pack |
| 608ZZ | 8 x 22 x 7mm | 4 pack |
| 699ZZ | 9 x 20 x 6mm | view |
| 6901Z (thin section) | 12 x 24 x 6mm | 4 pack |
| 6202RS | 15 x 35 x 11mm | 2 pack, 4 pack |
| MR18307-2RS (bicycle hub) | 18 x 30 x 7mm | 4 pack |
If the code has worn off
Measure the old bearing with a pair of callipers: the bore, the outer diameter and the width, in millimetres. Match those three numbers to the chart above. Check whether the old bearing had metal shields or rubber seals and choose the same type.
Signs a bearing needs replacing
A whining or grinding noise, a wobble at the spindle or a tool that runs hot are the usual signs. Our guide to bearings in power tools explains how to tell, and how to replace one.
See every size in the bearings collection.