Toyo Tire Rubber Co., Ltd.

Yusho Fuchikami

Keijiro Oda

Hiroshi Takino

Katsuji Kishida

Katsuharu Mitsutake

Takeyoshi Koyama

A pneumatic tire for preventing stones from being retained in the tread grooves whereby steps are provided on the lower half portion of the sidewalks of the grooves so as to extend from a side of the tread groove toward the center part thereof reducing the width of the groove in the lower part, and a plurality of narrow sipes are formed on end of the steps in a direction interesecting the tread groove.

Pneumatic tire with groove steps having sipes

A tire having superior cut resistance and less belt separation comprising a tread with steel cord belts in which a center rubber for middle part of the tread and a side rubber for both sides thereof are respectively formed of different rubber compositions, and in which at least an inner portion of the center rubber is composed of a rubber composition of superior cut resistance wherein either a natural rubber of a SBR blended natural rubber is compounded with carbon black of large iodine absorption number, silica and silane coupling agent expressed by a formula of (OR).sub.3 SiCnH.sub.2 nSmCnH.sub.2 nSi(OR).sub.3 or (OR).sub.3 SiCnH.sub.2 nX, while the side rubber is composed of a rubber composition having small heat build up.

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Osaka, Japan

Yusho Fuchikami