Rubber composition for tread used for studless tire and studless tire having tread using thereof

Abstract

It is an object of the present invention to lessen strain dependency of hardness of a tread rubber used for a studless tire, have good performance on snow and ice while securing rigidity on non-snow roads, and improve abrasion resistance. The present invention provides a rubber composition for tread used for a studless tire comprising 30 to 150 parts by weight as a total of (1) silica with a nitrogen absorption specific surface area of at most 100 m2/g and (2) silica with a nitrogen absorption specific surface area of at least 180 m2/g based on 100 parts by weight of a rubber component in which a content of a natural rubber and/or a polybutadiene rubber is at least 80% by weight, wherein contents of silica (1) and silica (2) satisfy the formula below: [Content of silica (1)]×0.2≦[Content of silica (2)]≦[Content of silica (1)]×6.5, tan δ peak temperature Tg is at most −50° C., and rubber hardness at 0° C. is at most 64.

Dependencies are inferred from the claim text.