Sumitomo Rubber Industries Limited

Toshio Koyama

Mitsuharu Koya

Hirokazu Takano

Akihiro Takeuchi

Keiji Higuchi

Masaru Araki

A pneumatic tire comprises a tread portion provided with a circumferential shoulder main groove, shoulder lateral grooves extending from the shoulder main groove toward a tread edge, and middle lateral grooves extending from the shoulder main groove toward a tire equatorial plane, the shoulder main groove extending in a zigzag manner through an axially innermost and outermost points alternately, each middle lateral groove extending from each innermost point of the shoulder main groove with an angle of 50-75 degrees with respect to a tire axial direction, and each shoulder lateral groove extending from the shoulder main groove with the same inclination direction with the middle lateral groove at an angle of 10-25 degrees with respect to the tire axial direction, wherein the number of shoulder lateral grooves is larger than the number of middle lateral grooves.

Pneumatic tire

A heavy duty pneumatic tire comprises a tread portion which is provide with wide circumferential grooves having a width Wm,of 4.0 mm to 20.0 mm and narrow circumferential grooves having a width Wm,of not less than 2.0 mm but less than 4.0 mm, and each region which is defined between one of the wide circumferential grooves and the axially adjacent narrow circumferential groove is provided with axial grooves extending from the wide circumferential groove to the narrow circumferential groove to circumferentially divide the region into blocks, wherein the axial grooves include variable-width grooves of which groove width increases from the wide circumferential groove to the narrow circumferential groove.

Heavy duty pneumatic tire including variable width grooves and constant width grooves

A pneumatic tire comprises an improved tread portion provided with blocks, each block provided with a sipe, the sipe extending across the block to have a first open end and a second open end, the sipe comprising three components forming a generally Z-shaped configuration, whereby the two parts divided by the sipe are engaged with each other to increase the block rigidity.

Pneumatic tire including sipes

A pneumatic radial tire, in which stone entrapment in the tread groove is prevented and the wet grip property is maintained, comprising: a tread provided with a central longitudinal groove on the central part thereof; the central longitudinal groove extending continuously zigzag in the circumferential direction of the tire along the equator of the tire to form a plurality of angled portions of the central longitudinal groove, and the groove provided in each zigzag edge portion with a platform; the platform in each zigzag edge portion being formed on one side of the sidewalls which is located more closely to the tire equator than the other side. The depth of the platforms from the tread surface to the platforms is in a range of 40 to 80% of the depth of the central longitudinal grooves; the circumferential length of the platform is in a range of 15 to 40% of the zigzag pitch of the central longitudinal groove; and the width of the platforms is in a range of 5 to 20% of the width of the central longitudinal groove.

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Kobe, Japan

Toshio Koyama