A commercial vehicles tire valve is a device that helps to control the inflation pressure of tires on trucks, buses, and other large commercial vehicles. It is typically a small metal or plastic valve that sits in the tire's sidewall. When the vehicle starts up, the air pressure inside the tires rises quickly as they fill with air from the atmosphere. The tire valve opens slightly to allow this initial burst of air into each tire, and then closes again to maintain consistent inflation pressure throughout the ride.