Tire
Tire means an item of motor vehicle equipment intended to interface between the road and a motor vehicle. The term includes all the tires of a vehicle, including the spare tire. For purposes of 579.21 through 579.24 and 579.27 of this part, this term also includes the tire inflation valves, tubes, and tire pressure monitoring and regulating systems, as well as all associated switches, control units, connective elements (such as wiring harnesses, hoses, piping, etc.), and mounting elements (such as brackets, fasteners, etc.).