Tires

Scope

These requirements apply to CMVs operated in interstate commerce.

Regulatory citations

• 49 CFR 393.75 — Tires

Key definitions

• Commercial motor vehicle (CMV): A self-propelled or towed motor vehicle used on a highway, in interstate commerce, that meets any one of the following criteria:
  • Has a gross vehicle weight rating (GVWR) or gross combination weight rating (GCWR), or gross vehicle weight (GVW) or gross combination weight (GCW), of 10,001 pounds or more, whichever is greater; or
  • Is designed or used to transport more than 8 passengers (including the driver) for compensation; or
  • Is designed or used to transport more than 15 passengers (including the driver), and not used to transport passengers for compensation; or
  • Is transporting hazardous materials of a type or quantity which requires placarding.

Summary of requirements

A CMV may not be operated on a tire that:

• Has body or belt material exposed through the tread or sidewall;
• Has any tread or sidewall separation;
• Is flat or has an audible leak; or
• Has a cut to the extent that the ply or belt material is exposed.

Regrooved, recapped, or retreaded tires may not be used on the front wheels of a bus.

Regrooved tires having a load carrying capacity equal to or greater than 4,920 pounds (2,232 kg) may not be used on the front wheels of any truck or truck tractor.

A motor vehicle may not be operated with speed-restricted tires labeled with a maximum speed of 55 mph or less in accordance with Federal Motor Vehicle Safety Standard (FMVSS) No. 119 (49 CFR 571.119, S6.5(e)) at speeds that exceed the rated limit of the tire.

A motor vehicle may not be operated with tires that carry a weight greater than that marked on the sidewall of the tire or, in the absence of such a marking, a weight greater than that specified for the tires in any of the publications of any of the organizations listed in FMVSS No. 119 (49 CFR 571.119, S5.1(b)) unless:

• The vehicle is being operated under the terms of a special permit issued by the state; and
• The vehicle is being operated at a reduced speed to compensate for the tire loading in excess of the manufacturer’s rated capacity for the tire. In no case, may the speed exceed 50 mph (80 km/hr.).

A motor vehicle may not be operated on a tire which has a cold inflation pressure less than that specified for the load being carried.

If the inflation pressure of the tire has been increased by heat because of recent operation of the vehicle, the cold inflation pressure must be estimated by subtracting the inflation buildup factor shown in the following table from the measured inflation pressure.