The radial inner cavity is the total movement that the other can do in the radial direction, while one of the bracelets is fixed.
| Class | meaning | typical use |
|---|---|---|
| C2 | less than normal | Precision applications with low thermal expansion |
| CN | Normal | Standard assembly and operating conditions |
| C3 | greater than normal | tight fit, high temperature; Common in electric motors |
| C4 | greater than C3 | High temperature and heavy conditions |
| C5 | The biggest | Special applications with very high temperature differences |
As the gap grows, the tolerance for working temperature and tight transitions increases; Excessive space can cause vibration and noise.