RADIAL TIRES

-Within the rubber are a series of plies of cord that act as reinforcement.

-made of layers of rubber and cords of polyester, steel, and/or other textile materials.

Radial tires lay all of the cord plies at 90 degrees to the direction of travel (that is, across the tire from lip to lip):

-This design avoids having the plies rub against each other as the tire flexes, reducing the rolling friction of the tire. --This allows vehicles with radial tires to achieve better fuel economy than vehicles with bias-ply tires. 

-It also accounts for the slightly "low on air" (bulging) look that radial tire sidewalls have, especially when compared to bias-ply tires.

-To add stiffness, the entire tire is surrounded by additional belts that are oriented along the direction of travel, made of tire cord.

-these belts can be made of steel (hence the term steel-belted radial) orPolyester or Aramid fibers such as Twaron and Kevlar.

-low radial tires separate the tire carcass into two separate systems:

• The radial cords in the sidewall allow it to act like a spring, giving flexibility and ride comfort.
• The rigid steel belts reinforce the tread region, giving high mileage and performance.

Each system can then be individually optimized for best performance.