Pneumatic tire for motorcycle

Abstract

The tread portion 2 is divided in the tire widthwise direction into five regions comprising the center tread region A, respective shoulder tread regions C, and respective intermediate tread regions B. A curved length in the tire widthwise direction of a tread surface of the center tread region A is in the range of 10 to 35% of the curved length in the tire widthwise direction of the entire tread surface, and the whole curved length in the tire widthwise direction of a tread surface of the shoulder tread regions C is in the range of 5 to 35% of the curved length in the tire widthwise direction of the entire tread surface. 100% Mod, i.e. the modulus at 100% elongation, of tread rubber forming the intermediate tread region B is larger than 100% Mod of tread rubber forming the center tread region A, and loss tangent of each shoulder tread region C is larger than loss tangent of the center tread region A.

1 . A pneumatic tire for motorcycle, including a pair of bead portions each having a bead core embedded therein, a pair of sidewall portions extending from the bead portions toward the outer side in the tire radial direction, and a tread portion extending over the respective sidewall portions, characterized in that:
 the tread portion is divided in the tire widthwise direction into five regions comprising the center tread region including the tire equatorial plane, respective shoulder tread regions each including a tread ground contact end, and respective intermediate tread regions each interposed by the center tread region and the corresponding shoulder tread region;   100% Mod of tread rubber forming the intermediate tread region is larger than 100% Mod of tread rubber forming the center tread region; and   loss tangent of each shoulder tread region is larger than loss tangent of the center tread region.   
   
   
       2 . The pneumatic tire for motorcycle of  claim 1 , wherein 100% Mod of the tread rubber forming the intermediate tread region is in the range of 1.3 to 2.1 MPa and loss tangent of each shoulder tread region is in the range of 0.3 to 0.4. 
   
   
       3 . The pneumatic tire for motorcycle of  claim 1 , wherein a curved length in the tire widthwise direction of a tread surface of the center tread region is in the range of 10 to 35% of the curved length in the tire widthwise direction of the entire tread surface, and the whole curved length in the tire widthwise direction of a tread surface of the shoulder tread regions is in the range of 5 to 35% of the curved length in the tire widthwise direction of the entire tread surface. 
   
   
       4 . The pneumatic tire for motorcycle of  claim 1 , wherein the sidewall portion includes an indication that the tire is for use as a rear tire of a motorcycle.