Sumitomo Rubber Industries Limited

Takahiro Kimishima

Minoru Nishi

Satoshi Tsuda

Kiyoto Maruoka

Atsushi Yamahira

Mitsuharu Koya

Masakazu Washizuka

Takeshi Kuroki

Jyunji Ohira

A tire includes a tread portion including at least one land region extending in a tire circumferential direction. The land region is provided with a plurality of axial groove portions curved so as to protrude in one direction in the tire circumferential direction in a plan view. The axial groove portions include first axial groove portions and second axial groove portions having different degree of curvature from the first axial groove portions.

Tire

A heavy duty tire has a tread portionwhich is divided into five inner, intermediate and outer rib-like land portions R, R, R, Rand R. The inner rib-like land portion Ris virtudally divided into half regions Rand Ron each side of a tire equator. The intermediate rib-like land portions Rand Rare virtually divided into tire equator-side half regions Rand R, and into ground-contact edge-side half regions Rand R. In a regular ground-contact state in which a normal load is applied, when total sums of ground-contact load applied to the half regions R, R, R, Rand Rare defined as P, P, P, Pand P

Heavy duty tire with tread portion having three longitudinal main grooves

In a ground-contact surface shape of a tire, when a tangent angle formed between an axial direction of the tire and a tangent X at each point P on a profile line of the tire is defined as &#x3b8;, a tangent angle &#x3b8;in a ground-contact end point Pd is 25&#xb0; or smaller. When a minimum value of the tangent angle &#x3b8; in a region Y which is separated away from a tire equator C by a distance in a range of not less than 0.4 times but not more than 0.7 times a half of the ground-contact width of the tread is defined as &#x3b8;, and a tangent angle at a 0.9 times point Pq which is separated away from the tire equator C by a distance of 0.9 times the half of the ground-contact width of the tread is defined as &#x3b8;, a difference (&#x3b8;) is set in a range of not less than &#x2212;10&#xb0; but not more than +10&#xb0;.

Heavy-duty tire having ground-contact surface shape

A heavy duty radial tire which is provided with traverse grooves extending between the tread edges and longitudinal grooves extending between the traverse grooves so as to form shoulder blocks arranged along each of the tread edges and inner blocks each disposed on the axially inside of one of the shoulder blocks. The longitudinal grooves between the shoulder blocks and the inner blocks have a depth Dga of 0.7 to 1.0 times the depth Dy of the traverse grooves, and the longitudinal grooves are each inclined at an acute angle with respect to the circumferential direction to have an axial extent range Y whose axial width W1 is in a range of from 1.0 to 10.0 times the width Wga. In a cross section of the tire under a normally inflated unloaded condition, the tread profile is made up of a center profile Si and a shoulder profile So. The shoulder profile So extends continuously from each of the axial ends of the center profile Si through an inflection point P to one of the tread edges. The center profile Si is a circular arc of a radius Rc having the center on the tire equatorial plane, and the shoulder profile So is a substantially straight line or alternatively an arc having less curvature than the center profile Si. The inflection point P is located within the axial extent range Y of the longitudinal grooves.

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Kobe, Japan

Takahiro Kimishima