PURPOSE: To enhance the mobility on a slipable road surface, heating, low fuel consumption of a tire having a two layer structure tread, by tread ratio of the outer surface rubber layer, and as well specifying the post-vulcanization characteristics of the inner surface rubber layer.
CONSTITUTION: An outer surface rubber 1 having a tread ratio of 0.5W0.9, a complex elastic modulus 3W8MPa at 70°C and a loss tangent 0.1W0.5, is formed with the use of 10W70pts.wt. of natural rubber and/or synthetic polyisoprene rubber, 10W50pts.wt. of poly butadiene rubber including 5pts.wt. of polybutadiene rubber in which the 1, 2 vinyle coupling content is less than 20wt% and more than one atomic groups having predetermined formulae are coupled to molecular chains, less than 60pts.wt. of styrene butadiene rubber containing 10W30wt% of styrene, 30W80pts.wt. of stretching oil having a viscosity gravity constant of 0.80W0.93, and 60W110 of carbon black. Further, the above-mentioned characteristics values of an inner surface rubber 2 is set at values of 2W7MPa and 0.04W 0.15, respectively.
HIRAKAWA HIROSHI
KAWAKAMI KINYA
MISAWA MAKOTO
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