U.S. Code of Federal Regulations
Regulations most recently checked for updates: Aug 27, 2025
The minimum diameters of axles for various axle loads shall be as follows:
| Axle load (in pounds) | Minimum
diameter of journal (in inches) | Minimum
diameter of wheel seat (in inches) | Minimum
diameter of center (in inches) |
|---|---|---|---|
| 50000 | 5
| 7
| 6
|
| 38000 | 5 | 6
| 5
|
| 31000 | 4
| 6
| 5
|
| 22000 | 3
| 5 | 4
|
| 15000 | 3
| 4
| 3
|
