Abstract: A heavy duty pneumatic tire, which allows the inside narrow-width belt layers to have a wide width as desired, and which suppresses the amount of strain generated at side edge portions of the belt layer to be sufficiently small thereby effectively preventing the separation of the belt layer, therefore the belt, in which two inside narrow-width belt layers 1B, 2B and two outside wide-width belt layers 3B, 4B, which have a larger width than the narrow-width belt layers, are sequentially disposed in the outer periphery side of the crown area of the radial carcass 5, wherein a portion of the wide-width belt layer 3B adjacent to the outer periphery side of the two narrow-width belt layers 1B, 2B, corresponding to side-edge vicinity of the narrow-width belt layer 2B of the outer periphery side is formed to be convex in radially outward direction.

Abstract: A heavy-duty pneumatic tire capable of sufficiently suppressing the amount of strain occurring in side edges of a belt layer is sufficiently suppressed, despite the required increase in width of the narrow belt layers on the inner layer side, so as to effectively prevent separation of the belt layer and, hence, separation of the belt. The tire includes two narrow belt layers (1B, 2B) on the inner layer side, and two wide belt layers (3B, 4B) on the outer layer side, which are larger in width than the narrow belt layers. The narrow belt layers and the wide belt layers are sequentially arranged on the outer circumferential side of a crown region of a radial carcass (5). The innermost narrow belt layer (1B) has side edges that are convex radially outwards.

Abstract: A heavy-duty pneumatic tire capable of sufficiently suppressing the amount of strain occurring in side edges of a belt layer is sufficiently suppressed, despite the required increase in width of the narrow belt layers on the inner layer side, so as to effectively prevent separation of the belt layer and, hence, separation of the belt. The tire includes two narrow belt layers (1B, 2B) on the inner layer side, and two wide belt layers (3B, 4B) on the outer layer side, which are larger in width than the narrow belt layers. The narrow belt layers and the wide belt layers are sequentially arranged on the outer circumferential side of a crown region of a radial carcass (5). The innermost narrow belt layer (1B) has side edges that are convex radially outwards.

Abstract: A heavy duty pneumatic tire, which allows the inside narrow-width belt layers to have a wide width as desired, and which suppresses the amount of strain generated at side edge portions of the belt layer to be sufficiently small thereby effectively preventing the separation of the belt layer, therefore the belt, in which two inside narrow-width belt layers 1B, 2B and two outside wide-width belt layers 3B, 4B, which have a larger width than the narrow-width belt layers, are sequentially disposed in the outer periphery side of the crown area of the radial carcass 5, wherein a portion of the wide-width belt layer 3B adjacent to the outer periphery side of the two narrow-width belt layers 1B, 2B, corresponding to side-edge vicinity of the narrow-width belt layer 2B of the outer periphery side is formed to be convex in radially outward direction.

Abstract: There is provided a pneumatic tire having an aspect ratio of not less than 60 and considerably improving run flat durability as compared with the conventional type of the run flat tire, wherein at least one cushion rubber layer having a loss tangent lower than a loss tangent (tan ?) of a coating rubber for cords of a carcass ply is arranged between an end portion of a belt and a reinforcing rubber layer in a shoulder region and between mutually adjacent tire constitutional members. And also, when the carcass is comprised of plural plies, at least one ply is separated off in a zone beneath the belt, whereby the ride comfort against vibrations can be more improved.

Abstract: This invention is concerned with a radial tire, particularly a heavy duty radial tire aiming at the improvement of durability, and is characterized by rendering a ratio W2/W1 of width W1 of a belt layer located side a carcass to width W2 of the remaining belt layer in small slant belt layers arranged at a width corresponding to 0.25–0.50 times a tread width in a widthwise direction of the tire, whereby growth and progress of cracks in the vicinity of cord ends of cords used in the belt resulting in separation failure at widthwise ends of the belt are effectively prevented to overcome a weak point in the tread reinforcement of the radial tire.

Abstract: There is provided a pneumatic tire having an aspect ratio of not less than 60 and considerably improving run flat durability as compared with the conventional type of the run flat tire, wherein at least one cushion rubber layer having a loss tangent lower than a loss tangent (tan ?) of a coating rubber for cords of a carcass ply is arranged between an end portion of a belt and a reinforcing rubber layer in a shoulder region and between mutually adjacent tire constitutional members. And also, when the carcass is comprised of plural plies, at least one ply is separated off in a zone beneath the belt, whereby the ride comfort against vibrations can be more improved.

Abstract: There is provided a pneumatic tire having an aspect ratio of not less than 60 and considerably improving run flat durability as compared with the conventional type of the run flat tire, wherein at least one cushion rubber layer having a loss tangent lower than a loss tangent (tan ?) of a coating rubber for cords of a carcass ply is arranged between an end portion of a belt and a reinforcing rubber layer in a shoulder region and between mutually adjacent tire constitutional members. And also, when the carcass is comprised of plural plies, at least one ply is separated off in a zone beneath the belt, whereby the ride comfort against vibrations can be more improved.

Abstract: A rubber composition having excellent heat resistance and a pneumatic tire produced by using this rubber composition are provided. The rubber composition has, in a curve exhibiting a change in dynamic storage modulus during elevation of temperature, an intersection of an extrapolation line of a portion in which the dynamic storage modulus is approximately constant before rapidly decreasing at temperatures higher than 100° C. and an extrapolation line of a portion in which the dynamic storage modulus rapidly decreases, at a temperature of 170° C. or higher.

Abstract: A pneumatic tire having an aspect ratio of not less than 60 comprises a radial carcass of one or more plies, a belt, a bead filler rubber and a rubber reinforcing layer of substantially a crescent shape in section extending from a position near to a bead core to a position near to a tread end along an inner surface of an innermost carcass ply, wherein at least one rubber protection sheet being relatively soft is disposed between the bead filler rubber and the carcass ply surrounding it and/or between the rubber reinforcing layer and the carcass ply nearest thereto.

Abstract: This invention is concerned with a radial tire, particularly a heavy duty radial tire aiming at the improvement of durability, and is characterized by rendering a ratio W2/W1 of width W1 of a belt layer located side a carcass to width W2 of the remaining belt layer in small slant belt layers arranged at a width corresponding to 0.25-0.50 times a tread width in a widthwise direction of the tire, whereby growth and progress of cracks in the vicinity of cord ends of cords used in the belt resulting in separation failure at widthwise ends of the belt are effectively prevented to overcome a weak point in the tread reinforcement of the radial tire.

Abstract: In a heavy duty pneumatic radial tire having a lug pattern formed on both sides of a tread portion, each of lug grooves forming lugs is extended from a position separated from an equatorial plane of the tire by a given distance up to each of tread ends and has a platform on a region ranging from a top end portion near to the equatorial plane to a central portion in a longitudinal direction of the lug groove so as to satisfy such a surface shape that a groove depth at the top end portion is made shallower than a groove depth at the central portion.

Abstract: There is provided a pneumatic tire having an aspect ratio of not less than 60 and considerably improving run flat durability as compared with the conventional type of the run flat tire, wherein at least one cushion rubber layer having a loss tangent lower than a loss tangent (tan &dgr;) of a coating rubber for cords of a carcass ply is arranged between an end portion of a belt and a reinforcing rubber layer in a shoulder region and between mutually adjacent tire constitutional members. And also, when the carcass is comprised of plural plies, at least one ply is separated off in a zone beneath the belt, whereby the ride comfort against vibrations can be more improved.

Abstract: A pneumatic tire having an aspect ratio of not less than 60 comprises a radial carcass of one or more plies, a belt, a bead filler rubber and a rubber reinforcing layer of substantially a crescent shape in section extending from a position near to a bead core to a position near to a tread end along an inner surface of an innermost carcass ply, wherein at least one rubber protection sheet being relatively soft is disposed between the bead filler rubber and the carcass ply surrounding it and/or between the rubber reinforcing layer and the carcass ply nearest thereto.

Abstract: A rubber-steel cord composite comprising a steel cord having, in a planar image of the steel cord formed by X-rays passing through the steel cord, a fraction R of the total area occupied by filaments of from 0.45 or more to 0.95 or less in an arbitrarily selected portion of the steel cord having a length of 15 mm in an axial direction of the cord, is provided. The length of 15 mm in an axial direction of the cord means a length of 15 mm in an axial direction of an actual cord and the fraction R of the total area occupied by the filaments is expressed as R=F/A, wherein A represents the total area of the cord and F represents the area of the cord occupied by the filaments. An object of the present invention is to provide a pneumatic tire for passenger cars that shows no separation of the interface of adhesion during use, particularly during use in the run-flat condition, and exhibits excellent durability.

Abstract: There is provided a pneumatic tire having an aspect ratio of not less than 60 and considerably improving run flat durability as compared with the conventional type of the run flat tire, wherein at least one cushion rubber layer having a loss tangent lower than a loss tangent (tan &dgr;) of a coating rubber for cords of a carcass ply is arranged between an end portion of a belt and a reinforcing rubber layer in a shoulder region and between mutually adjacent tire constitutional members. And also, when the carcass is comprised of plural plies, at least one ply is separated off in a zone beneath the belt, whereby the ride comfort against vibrations can be more improved.

Abstract: A rubber composition having excellent heat resistance and a pneumatic tire produced by using this rubber composition are provided.

Abstract: The present invention provides a pneumatic safety tire comprising a pair of left and right bead cores, a carcass layer, a multi-layer belt portion, a tread portion, and a pair of side wall portions disposed at the left and right of said tread portion, wherein at least one sheet of a rubber-filament fiber composite formed from filament fibers and a rubber component is disposed at said side wall portions in a vicinity of said carcass layer. The safety tire of the present invention maintains the properties during ordinary use under the inflated condition at high levels, has a light weight, and shows remarkably improved properties during use under the run-flat condition.

Abstract: A rubber-steel cord composite comprising a steel cord having, in a planar image of the steel cord formed by X-rays passing through the steel cord, a fraction R of the total area occupied by filaments of from 0.45 or more to 0.95 or less in an arbitrarily selected portion of the steel cord having a length of 15 mm in an axial direction of the cord, is provided. The length of 15 mm in an axial direction of the cord means a length of 15 mm in an axial direction of an actual cord and the fraction R of the total area occupied by the filaments is expressed as R=F/A, wherein A represents the total area of the cord and F represents the area of the cord occupied by the filaments.

Abstract: A pneumatic tire for passenger cars comprises bead cores, a carcass layer, a tread portion, and side wall portions, wherein a rubber reinforcing layer having a crescent-shaped cross-section and at least one sheet of a rubber-filament fiber composite having a thickness measured under a pressure of 20 g/cm2 of 0.05 to 2.0 mm which is formed from a rubber component and filaments having a diameter or a maximum cross-sectional dimension of 0.0001 to 0.1 mm and a length of 8 mm or more are disposed in said side wall portions. Reinforcing cords of carcass plies are made of an aliphatic polyamide fiber having a melting point of 250° C. or higher.