| 摘要 |
<p>Provided is a motorbike pneumatic tire, which is improved in a high-speed durability at a straight running time, while keeping the gripping performance at a cornering time, by making proper the distribution of a loss tangent of tread rubber constituting the tread portion. The motorbike pneumatic tire comprises a pair of bead portions (1) having bead cores buried therein, a pair of sidewall portions (2) extending from the bead portions (1) to the radially outer sides of the tire, and a tread portion (3) extending between the two sidewall portions (2). The motorbike pneumatic tire is characterized in that the tread portion (3) is composed of at least four tread portion regions which are different from one another in the loss tangents of the rubber constituting the adjoining regions, as viewed in the section of the tire width direction, and in that the loss tangent of the rubber constituting a central tread portion region (5) or the tread portion region containing a tire equatorial plane (4) in the tread portion region is smaller than the loss tangent of the rubber constituting other tread portion regions (6).</p> |
