RADIAL PNEUMATIC TYRE:CARCASS PLY OF LOW TWIST YARN AND SHORT TURN-UP AT BEADS

摘要

A pneumatic radial ply tire in which the body ply is formed of a low twist yarn having between three and six turns-per-inch. The body ply terminates in relatively low turn-up ends extending along the side walls a distance between 10% and 30% of the tire section height and out of the area of cyclic stress and oscillation in the side walls of the tire. A relatively high, wide and hard bead filler is located within a bead portion of the tire and has a height between 20% and 50% of the tire section height with a width of between 15% and 35% of the bead filler height. The bead filler has a hardness of between 75 and 98 on the Shore A scale. The ply yarn preferably is polyester and the individual low twist strands are arranged in a parallel relationship and is preferably free of transverse cross strands known as wefts or picks. The combination of low twist yarn, low turn-up body ply ends and bead filler size and hardness provides a tire having increased durability and uniformity at a lower cost.