Pneumatic radial tire having an excellent steering stability

Claim 1

A radial tire comprising; a pair of annular bead rings, a carcass composed of at least one radially arranged textile cord ply toroidally extending from the bead rings through side portions to a crown portion, the bead portion being reinforced by a rubber filter interposed between a turn-up portion of the carcass ply wound around the bead ring from the inside toward the outside thereof and the carcass and extending from the upper portion of the bead ring to the side portion region, and the crown portion being reinforced by an inextensible belt layer superimposed about the carcass, said rubber filler having a dynamic modulus of elasticity of 600 to 1,500 kg/cm 2 and, a single additional layer interposed between the carcass and the rubber filler, said single additional layer consisting of steel cords inclined at an angle within a range between 45° and 75° with respect to the carcass cord, said single additional layer closely adhering to said rubber filler and arranged over a range which is 50% to 75% of the tire sectional height defined by the distance in the radial direction from the bead portion base to the tread top point, an upper end of said rubber filler extending toward said tread portion beyond an upper end of said additional layer and a neutral axis of bending deformation produced at an area disposed in said rubber filler in the bead portion when the tire is subjected to a load passes through said rubber filler along the side of said single additional layer.