What are the regulatory requirements for tires?

The following points summarize the regulations for tires:

• The front tires on a bus, truck, or truck tractor must have a tread depth of at least 4/32 inch when measured at any point on a major tread groove.
• All other tires must have a minimum tread depth of 2/32 inch when measured at any point on a major tread groove.
• No tire may be used if it has ply or belt material showing, has tread or sidewall separation, is flat or has an audible leak, or has a cut or gouge that reaches the ply or belt material.
• Regrooved tires having a load-carrying capacity of 4,920 pounds or more cannot be used on front wheels of trucks and truck tractors.
• Regrooved, recapped, or retreaded tires are prohibited on the front wheels of buses.
• Vehicles equipped with speed-restricted tires that are labeled with a maximum speed of 55 mph or less may not be operated at speeds that exceed the rated limit of the tire.
• No tire shall be carrying more weight than it is rated for, based on the load rating marked on the sidewall of the tire. In the absence of the sidewall marking, the loading must be in conformance with the tire load ratings specified in 571.119. The only exceptions are manufactured homes built before January 1, 2002 (they are allowed to exceed the marked tire rating by up to 18 percent and must operate at 50 mph or less), and vehicles operating under terms of a special permit issued by the state that are being operated at a reduced speed (50 mph or less).
• No vehicle shall be operated on a tire which has a cold inflation pressure less than that specified for the load being carried.