Abstract: A pneumatic radial tire for heavy load vehicles including an improved bead portion reinforcing construction constructed such that the cords of a reinforcing layer along the outside of a carcass ply are inclined on a circle formed by the upper end of a turn-up region of the carcass ply at an angle of 50.degree. to 70.degree. with respect to the radial plane of the tire and have an air gap ratio .delta. of 38% to 60% measured at a region where the cords of the reinforcing layer cross with a line tangent to a curved surface of a rim flange and extending in parallel with the rotary axis of the tire and given by the following formula ##EQU1## where b is a distance between two midlines of two adjacent cords, measured perpendicular to the cords, and c is a cord diameter.

Abstract: A noiseless lug tire which runs at a high speed under a heavy load and which satisfies the following conditions.(1) A ratio Wg/Wl is equal to or smaller than 1.0.(2) Each transverse groove for delimiting lugs is not inclined toward an opening of the transverse groove at the kickout side of each lug.(3) Each transverse groove is inclined toward the opening at the stepin side of each lug at an angle of at most 22.degree..(4) Each portion of a center line of the transverse groove in a substantially total region of a length L of the transverse groove is inclined with respect to the meridian line of the tire at an angle within a range from at most 15.degree. measured in a direction opposite to the inclination direction of the transverse groove as a whole to at most 60.degree. measured in the same direction as the inclination direction of the transverse groove as a whole.

Abstract: A pneumatic tire having anti-transverse skid property for vehicles which run at a high speed under a heavy load comprising a depression provided in the tire sidewall near the shoulder and for circumferentially dividing the tire sidewall near the shoulder into a number of lands and a shoulder side groove provided in the land, the edge lines formed between the wall of the depression and shoulder side groove and the tire sidewall outer surface being designed so that the anti-transverse skid property of the tire is improved.

Abstract: A highly durable pneumatic tire comprising a carcass body formed by a number of laminated bias laid plies each including rubberized organic textile cords is disclosed. The carcass body is composed of at least two kinds of ply groups whose cords are the same in diameter, but different in the number of twists per unit length, the cords of the outermost ply group of the carcass having the number of twists which is 5% to 30% times larger than the number of twists of the ply group adjacent to the outermost ply group and located at the inner portion in the carcass and which is at least equal to the number of twists of the cords of the innermost ply group, and the cords of the innermost ply group of the carcass having the number of twists which is 5% to 30% times larger than the number of twists of the ply group adjacent to the innermost ply group and located at the outer portion in the carcass.

Abstract: A tread reinforcing construction of a pneumatic radial tire for heavy-load vehicles is disclosed. The tread reinforcing construction comprises a combination of a rubberized belt superimposed about a rubberized carcass ply and at least one additional rubberized reinforcing layer interposed between the belt and a tread rubber. The additional rubberized reinforcing layer is composed of a reinforcing element embedded therein and formed of a helically formed filament or a bundle of at least two helically formed filaments assembled together without twisting at random.

Abstract: A rubber reinforcing member and a method of manufacturing the same are disclosed. The rubber reinforcing member is composed of rubber and a number of filamentous elements embedded therein. The filamentous element is formed of a metal or a material having a strength similar to that of the metal and has a helix on at least one end portion thereof.

Abstract: An improved belt construction for a radial or semi-radial tire comprising a reinforcing belt layer including helically formed filaments is disclosed. Between main belt layers is interposed an intermediate reinforcing layer composed of a reinforcing element formed of helically formed filaments each having a tensile breaking strength of at least 140 kg/mm.sup.2 and elongation at tensile breaking strength of at least 1.2 times the smallest elongation at tensile breaking strength of the cords of the main belt layers. The intermediate reinforcing layer as a whole is extensible and compressible.

Abstract: A pneumatic radial tire comprising a carcass, and a belt interposed between a tread and the carcass composed of at least two main cord layers whose cords are formed of an inextensible material such as a steel cord is disclosed. The tire further comprises at least one rubberized reinforcing layer interposed between the belt and the carcass and containing reinforcing elements. The reinforcing element is formed of a helically formed filament or a bundle of a plurality of helically formed filaments. The filament has a tensile breaking strength of at least 140 kg/mm.sup.2 and elongation at tensile breaking strength which is at least 1.2 times the smallest elongation at tensile breaking strength of the main cord layers of the belt. The rubberized reinforcing layer as a whole is extensible and compressible.

Abstract: A pneumatic tire for off-road vehicles comprising a multi-layered carcass and a breaker superimposed about the carcass. The carcass is composed of rubberized ply layers each containing cords formed of organic fiber and inclined at an angle of 23.degree. to 45.degree. with respect to the equatorial line of the tire. The cords of approximately one-half of the carcass plies extend in an opposite direction to the cords associated with the remaining plies. The breaker is composed of at least one rubberized layer each containing reinforcing elements formed of a plurality of filaments whose material having a tensile strength of at least 140 Kg/mm.sup.2, the reinforcing element being inclined at an angle which is not larger than a selected angle of the carcass cord by at least 5.degree. and not smaller than the selected angle of the carcass cord by at least 15.degree.. At least one rubberized layer of the breaker disposed near the tread is extended over a width of 40 to 60% of the tread width.

Abstract: A pneumatic tire for off-road vehicles, which is highly durable under heavy load conditions is disclosed. The tire makes use as its breaker of a reinforcing element formed of material having a high cut resistant property such as steel or glass. The least possible number of those plies of a plurality of rubberized ply layers of a carcass body which extend from a crown portion of the tire through both side portions up to both bead members and which can substantially withstand internal pressure applied to the tire and external force subjected thereto is determined on the basis of a fundamental safety factor .xi. and which lies within a range of a correction safety factor .eta. which depends on the use and type of the tire and the depth of tread groove.

Abstract: This invention relates to an improvement in a pneumatic tire for construction vehicles. The improved tire makes use of a steel cord breaker, but can prevent mechanical and thermal separations in the tire. Breaker rubberized cords are designed to have a gap ratio given by ##EQU1## preferably 0.72 to 0.80, for the purpose of restraining the mechanical separation, where D is a distance between centers of two adjacent cords and d is a diameter of the cord. A tread rubber layer is designed to have a ratio R of a skid base S to a tire section height H given by ##EQU2## FOR THE PURPOSE OF RESTRAINING THE THERMAL SEPARATION.

Abstract: A wide base type pneumatic tire for construction vehicle has a given sectional thickness distribution of crown portion, a tread pattern of lug arrangement and a crown radius of at least 75% of overall tire width, and is usable for dump truck, earth mover and the like.