Sumitomo Rubber Industries Limited

Noriko Kishimoto

Akio Ikeda

Naoki Kageyama

Masaki Terashima

A studless tire capable of exhibiting excellent performances on both icy road and snow-covered road, including tread portionhaving a pair of middle circumferential grooveseach extending in a region between 15% and 25% of tread width TW from tire equator C to provide crown region CR between the middle groovesand a pair of shoulder regions Sh between the middle grooveand ground contact edge E, wherein the crown region CR includes rows R, Rof blocks B having sipes S and defined by zigzag inner circumferential groovesand crown lateral grooves, each shoulder region Sh includes rows R, Rof blocks B having sipes S and defined by linear outer circumferential groovesand shoulder lateral grooves, and groove area rate Gs (%) of shoulder regions Sh is larger than groove area rate Gc (%) of crown region CR so that the difference (Gs&#x2212;Gc) is from 3 to 7%.

Studless tire

A pneumatic tire capable of preventing wandering without impairing wear resistance, including tread portionhaving circumferential shoulder groovesextending at locations near ground contact edges E and lateral shoulder groovesextending between circumferential grooveand ground contact edge E, and having square shoulders such that tread surfaceand buttress faceextending radially inwardly and axially outwardly from ground contact edge E intersects to form an edge or corner, wherein each shoulder block Bis provided with circumferential sipein a region apart axially inwardly from ground contact edge E by a distance of 2 mm or more and a distance of 10 mm or less, the buttress faceis provided with recessextending circumferentially in at least a part of projection region Z obtained by projecting circumferential sipeonto buttress face, and radially innermost endB of recessis located at a radial position corresponding to a region ranging from 50 to 100% of the depth of circumferential sipe

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Kobe, Japan

Noriko Kishimoto