Provided is a tire such that both tire weight reduction and high durability can be achieved by establishing a technology capable of ensuring the sufficient effect of preventing diameter growth even when the amount of steel used in a belt layer is decreased. The tire includes: two or more crossing belt layers 4 including rubberized layers of steel cords tilting and extending at an angle of 10 to 30 with respect to a tire equatorial plane, the rubberized layers being arranged such that the directions of the cords intersect each other; and a high-angle bell layer 3 including a rubberized layer of steel cords tilting and extending at an angle which is 5 or more greater than the angle of the crossing belt layers. The mass of the steel cords per unit area included in the high-angle belt layer is 85% or less of the mass of the steel cords per unit area included in the crossing belt layers, and compressive rigidity per unit area in a cross section orthogonal to the longitudinal direction of the steel cords of the high-angle belt layer is greater than compressive rigidity per unit area in a cross section orthogonal to the longitudinal direction of the steel cords of the crossing belt layers.

Provided is a tire such that both tire weight reduction and high durability can be achieved by establishing a technology capable of ensuring the sufficient effect of preventing diameter growth even when the amount of steel used in a belt layer is decreased. The tire includes: two or more crossing belt layers 4 including rubberized layers of steel cords tilting and extending at an angle of 10 to 30 with respect to a tire equatorial plane, the rubberized layers being arranged such that the directions of the cords intersect each other; and a high-angle bell layer 3 including a rubberized layer of steel cords tilting and extending at an angle which is 5 or more greater than the angle of the crossing belt layers. The mass of the steel cords per unit area included in the high-angle belt layer is 85% or less of the mass of the steel cords per unit area included in the crossing belt layers, and compressive rigidity per unit area in a cross section orthogonal to the longitudinal direction of the steel cords of the high-angle belt layer is greater than compressive rigidity per unit area in a cross section orthogonal to the longitudinal direction of the steel cords of the crossing belt layers.

A steel cord with a construction of m+n having a first group of core filaments having a number of m and a second group of sheath filaments having a number of n, the second group and the first group are twisted around each other with the same twist pitch and same twist direction, wherein the core filaments are not twisted with each other, the core filaments are parallel or have a twist pitch being more than 300 mm, and the sheath filaments have a twist pitch being less than or equal to 30 mm, the core filaments have an average tensile strength Tc in MPa when being un-ravelled from said steel cord, the sheath filaments have an average tensile strength Ts in MPa when being un-ravelled from said steel cord, Tc and Ts satisfy: 5<(TcTs)<200. The steel cord has high breaking load and high production efficiency without cost increase.