What is the minimum tread depth on a semi?

The minimum tread depth for semi-truck tires, as regulated by the Federal Motor Carrier Safety Administration (FMCSA), is 4/32 of an inch for steer tires and 2/32 of an inch for drive and trailer tires. However, many safety experts recommend replacing tires when tread depth reaches 5/32 of an inch to ensure optimal traction and safety, especially in wet conditions. Regularly checking and maintaining tire tread depth is crucial for safe operation.