Definition (Source: Wikipedia)
***Tires or tyres (in American and British English, respectively) are pneumatic enclosures used to protect and enhance the effect of wheels.
Tires are used on many types of vehicles, from cars to earthmovers to aircraft. Tires enable vehicle performance by providing for traction, braking, steering, and load support. Tires are inflated with air, which provides a flexible cushion between the vehicle and the road that smoothes out shock and provides for a comfortable ride.