Bias vs. Radial Tires
Radial and bias refer to how the plies are arranged within the tire.
In a bias tire, the plies cross over each other, which makes the tire very stiff. Both the tread and the casing function as one entity.
In a radial tire, the plies are parallel to each other, so the tire is more flexible. The tread functions independently from the casing. Radial tires help reduce operating costs; they are lighter, run cooler, and last longer than bias tires.
Parts of an Aircraft Tire
The tread is made of rubber. It protects the rest of the tire and provides traction for the tire on the runway.
The plies are located under the tread. Layers of plies give the tire the strength to hold the inflation pressure in the tire.
The liner keeps air (or nitrogen) from leaking from the tire. The liner is protected by the plies and the tread
(on the “top” of the tire) and by the side-wall (on the “sides” of the tire).
Most aircraft tires are filled with nitrogen instead of air because it is non-combustible (will not burn).
Did You Know?
Michelin manufactures general aviation, commercial, and military tires. Michelin researches, designs, markets, and manufactures some of these tires in Greenville, SC.
Aircraft tires support the weight of the aircraft when it is on the ground. Aircraft tires provide a stable ride when the aircraft is taxiing.
Aircraft tires are rated for speeds of up to 235 miles per hour, which is the speed of a Formula 1 racecar! They may see these speeds during take off and landing.
Aircraft tires withstand extreme swings in air temperatures - as high as 120° F (49° C) during taxi and take off and as low as -67° F (-55° C) at cruising altitudes.
Aircraft tires absorb the shock of landing and support the weight of the aircraft during a landing. Aircraft tires also withstand the heat generated by the friction of braking (up to 300° F/150° C).
Did you know?
Some aircraft tires can support up to 75,000 pounds. That’s the equivalent of 5 elephants! A typical car tire can support about 1,600 pounds.
Some aircraft tires can be inflated to over 275 PSI (pounds per square inch). That’s the equivalent of being 179 meters (587 feet) deep in the ocean!
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Here is the link to the Michelin aircraft tire site: www.airmichelin.com