RUBBER COMPOSITION AND TIRE

The present invention aims to provide rubber compositions and tires which provide improved overall performance in terms of wet grip performance, dry grip performance, and fuel economy. The present invention relates to a rubber composition having a hardness that reversibly changes with water and satisfying the following relationships (1) and (2): Hardness when dry−Hardness when water-wet≥1 (1) wherein each hardness represents the JIS-A hardness at 25° C. of the rubber composition; and tan δ at 70° C. when dry