Radial tire with lower rolling resistance, includes inner tread rubber layer, having harder, higher-hysteresis region near edge, resisting normally-higher deformation in shoulder zone

摘要

In the inner region against the belt ply, over a first axial zone within the belt width, from one side over the crown to the other, a first tread rubber (15) composition is used. A second region (17) connects axially to the first axial region and is made of a second composition, which is harder, and especially has greater hysteresis, than the first. In the inner region against the belt ply, over a first axial zone within the belt width, from one side over the crown to the other, a first tread rubber (15) composition is used. A second region (17) connects axially to the first axial region. This extends axially from the belt width, beyond the axial location of the belt ply edge, into the tire shoulder region. This is made of a second composition, which is harder, and especially has greater hysteresis, than the first. Preferred features: In the radially outer region of the tread a unitary rubber mixture is formed over the entire axial extent. The second region between an axial position inside the belt extent, has axial spacing from the belt edge corresponding to 5%-30% of the belt width. The second rubber mixture has a Shore hardness in the range 65-78 Shore A, that of the first mixture is 5 Shore A units less. The radially inner region has a radial thickness of at least 0.8 mm.