Abstract: A pneumatic radial tire having an improved bead portion reinforcing construction is disclosed. The radial tire comprises a bead portion reinforcing band disposed along the bead portion formed by folding the ply of the carcass body around the bead ring. The bead portion reinforcing band comprises at least one chipper layer. The chipper is composed of a reinforcing element embedded in rubber and formed of 1 to 50 helically formed filaments. The reinforcing element has a modulus of elasticity of 0.029.times.10.sup.4 kg/mm.sup.2 to 1.60.times.10.sup.4 kg/mm.sup.2 and is inclined at a given angle with respect to the ply cords of the carcass body so as to make the chipper as a whole extensible and rigid.

Abstract: A radial tire provided with a tread pattern suitable for travel on paved roads at a high speed is disclosed.The tread pattern is of a block-rib type which is constructed to satisfy the following conditions, i.e.(1) W.sub.1 =(5-9%) TW(2) W.sub.2 =(0.5-2.5%) TW(3) 60% BW.gtoreq.A and A.gtoreq.20% TW(4) B.sub.2 =(1.0-2.0) B.sub.1where W.sub.1 is a width of a wide circumferential groove, TW is a tread width, W.sub.2 is a width of a narrow circumferential groove, BW is an effective width of a belt, A is a width of a tread center portion, B.sub.1 is a tread side portion facing the tread center portion and B.sub.2 is a tread side portion facing two shoulder portions.

Abstract: Reinforcing structure at bead sections of radial tires for heavy load comprising(1) at least one carcass ply(2) at least one chafer(3) a circular triangular composite rubber stiffener composed of a lower half portion having a higher modulus and an upper half portion having a lower modulus, which is disposed between a case main portion and the turned-over carcass ply portion and(4) a reinforcing member composed of at least two rubberized organic fiber cord layers arranged at the case main portion, the inward end in the radial direction of said reinforcing member being locked with the bead base and said reinforcing member being disposed along a circular region having a given height at the case main portion.

Abstract: A reinforced construction of bead portions of radial tires for heavy load vehicles such as trucks, buses etc., which is well balanced in rigidity and which has an excellent durability is disclosed. The construction includes a first reinforcing layer and a second reinforcing layer, the first reinforcing layer being substantially continuously extended from a height covering both the upper ends of the second reinforcing layer and of the turned-up portion of the carcass ply to the inside surface of the carcass ply, the second reinforcing layer being interposed between the turned-up portion of the carcass ply and the first reinforcing layer, the axially inside portion of said first reinforcing layer which is disposed along the inside of the carcass ply having an upper end whose height h.sub.1 from the bead base portion is given byh.sub.1 =(0.8 to 2.5)h.sub.0where h.sub.

Abstract: A pneumatic radial tire for heavy load vehicles comprises a carcass and a belt for reinforcement of the carcass, said belt including tension members composed of at least two rubberized metal cords crossing with each other at a cord angle of not more than 25.degree. with respect to equatorial plane of tire, in which said metal cords is coated with a rubber having a modulus of elasticity of 40-80 Kg/cm.sup.2, a distance between the cords in each tension member is widened to 0.2-0.75 d based on a diameter d of the cord, and an interlaminar cord distance D between the tension members is uniformly shortened to 0.2-0.4 d at a central region extending within 50-80% of a superposed width of the tension members.

Abstract: A radial tire having a highly durable bead structure, comprising a carcass ply having a high modulus of elasticity is disclosed. The bead is constructed to satisfy the following conditions, i.e.,h.sub.2 = (1/10 to 1/2)h.sub.0, and (1)d = (1/30 to 1/5)D (2)where h.sub.0 is a vertical height of the upper end of a turn up portion of the carcass ply measured from a base of the bead, h.sub.2 is a vertical distances from the upper end of the turn up portion of the carcass ply to the upper end of an inner reinforcing cord layer, after the tire has been mounted and inflated d is an interlayer gauge of a space formed between the turn up portion of the carcass ply and an outer reinforcing cord layer and measured on a line passing through the upper end of the turn up portion of the carcass ply and perpendicular to the carcass ply and D is a thickness of that portion of the bead which is measured on said line. A rubber having a modulus of elasticity of 20 to 100 Kg/cm.sup.2 at 100% elongation is inserted into said space.