Sumitomo Rubber Industries Limited

Kozo Yoshimura

Ryota Ikeda

Masahiro Tatsuta

Tetsuya Maekawa

Natsumi Funase

Tsukasa Kitatani

A tire includes a tread portion including first and second tread edges, three or more circumferential grooves, and four or more land portions. The circumferential grooves include a first shoulder circumferential groove nearest to the first tread edge. Each land portion is provided with only sipes and is not provided with lateral grooves. The land portions include a first shoulder land portion having the first tread edge, and a first middle land portion adjacent to the first shoulder land portion. The first middle land portion is provided with first middle sipes traversing the first middle land portion completely in the tire axial direction. The first shoulder land portion is provided with first shoulder sipes extending from the first shoulder circumferential groove to the first tread edge. The first shoulder sipes have a circumferential pitch length smaller than a circumferential pitch length of the first middle sipes.

Tire

A tire has a tread portion provided with three or four circumferential grooves including a shoulder circumferential groove to form a shoulder land region and a middle land region. The middle land region is provided with a middle circumferential sipe and middle lateral sipes. The shoulder land region is provided with shoulder lateral grooves extending from the shoulder circumferential groove to a tread edge, and shoulder lateral sipes extending from the shoulder circumferential groove and terminated without reaching the tread edge.

A pneumatic tire includes a tread portion including a contact patch which occurs when the tire is mounted on a standard wheel rim with a standard pressure and loaded with a certain tire load at zero camber angle. The contact patch, on a respective tire load, defines a ratio Lc/Ls of a crown contact circumferential length Lc at an axial center of the contact patch to a shoulder contact circumferential length Ls at an axial location of 80% of an axial maximum width of the contact patch. The ratio Lc/Ls upon being loaded with 40%, of a standard tire load is equal to or less than 125% of the ratio Lc/Ls upon being loaded with 70% of the standard tire load.

Pneumatic tire

A tire is provided in a first half-tread portion with a first shoulder main groove and a first shoulder land regionD and a first middle land regionB on the axially outside and axially inside thereof, respectively. The first shoulder land regionD is divided into first shoulder blocksD each provided with a first shoulder chamfer portionat the corner portionbetween the ground contacting surface and the groove side wall of the first shoulder main grooveC. Both ends of the first shoulder chamfer portionterminate without being connected to the first shoulder transverse groovesD. The first middle land regionB is provided at the cornerbetween its ground contacting surface and the groove side wall of the first shoulder main groove with first middle chamfer portionseach positioned in a part of the range between the adjacent first middle rug groovesB. The first middle chamfer portionsare disposed so as face the first shoulder chamfer portions

Growing community of inventors

Kobe, Japan

Kozo Yoshimura