| 摘要 |
<p>A rubber composition for an under tread of a tire comprises: relative to 100 parts by weight of diene rubber, from 15 to 45 parts by weight of carbon black and from 3 to 30 parts by weight of silica. An N2SA of the carbon black is from 35 to 85 m2/g and a DBP absorption number of the carbon black is from 105 to 200 mL/100 g. A difference between a sulfur content of the rubber composition for the under tread (Y parts by weight) and a sulfur content of the rubber composition for coating that forms the belt layers (X parts by weight) (β=X−Y) is 4.5 or less, and a difference between the rubber hardness A of the cap tread and the rubber hardness B of the under tread (α=A−B) is from 5 to 12.</p> |
