AIRCRAFT TIRES

Aircraft tires are totally different from that of automotive tires.  A tire on a car has it easy compared to one on an aircraft. A car doesn't drive along a sun-baked, 120-degree F taxiway, then climb into sub-zero temps several miles above the Earth, hanging in a 100-mph wind, then come down and smash onto the ground at 80 miles an hour, maybe even bouncing a few times. Not just any tire is up to the mission.

Aircraft Tires fall into two distinct technologies - bias (also known as cross ply) and radial. Bias and radial tires are significantly different to each other and both technologies offer operators features and benefits that might be considered agreeable for particular applications. The aircraft tire is a composite structure of three basic materials:

• Rubber

• Nylon Cord

• Steel

The components are bonded together by vulcanization.

The tread in aircraft tires tends to be straight line while your car tires have much different tread patterns. Aircraft tires are filled up to nearly 200 PSI whereas car tire typically are filled up to 30 PSI.

Automotive tires are inflated with normal air. The tires of airplanes (at least the big ones) are inflated by nitrogen (instead of air). Air has a certain moisture content and it is generally very hard to remove this moisture. If an airplane tires were filled with air, at the flight altitude ice would form inside the tires since the temp up there is about -30 degrees F. Landing with a chunk of ice in the tire would make it out of balance and change the tire pressure. Tires would probably burst. On the other hand, nitrogen doesn't form a liquid till -173 C and pure nitrogen has almost no moisture. 

They are also subjected to tremendous forces on landing when they must accelerate very quickly. The friction on touch-down creates great heat within the tires and produces very high stresses in the walls of the carcass. Therefore, every effort is made to reduce or eliminate the deterioration caused over time by oxidation. Since normal atmospheric air is approximately 20% oxygen, the tires are inflated with 100% nitrogen - a relatively inert gas.  Jet airline tires are fused. When the fuse is heated it deflates the tire so they don't explode.

Aircraft tires do not typically have a definitive lifespan. It all depends on the airframe and how hard the landing is. Another factor that many people overlook is the main vs nosewheel tires. The main tires tend to last longer than the nosewheel tires. Depending on the aircraft this could vary from 10-200 landings. Once a tire is used up it isn't thrown away, it's retreaded up until the core becomes worn out.