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 and dry grip performance. The present invention relates to a rubber composition having a hardness that reversibly changes with water and satisfying the following relationship (1): Hardness when dry−Hardness when water-wet≥10 (1) wherein each hardness represents the JIS-A hardness at 25° C. of the rubber composition.