| 摘要 |
<p>There is provided a pneumatic tire in which a plurality of land portions are formed in a tread road-contacting surface, the total negative ratio N of the road-contacting surface is set in a range from 25% to 65%, and the depth D of each groove is set at 5mm or more. The plurality of land portions bite into a snow-covered surface, and a high tire performance on snow can be achieved. Further, in this pneumatic tire, sipes (the depth Sd of the sipe is given by D x alpha (0.1 < alpha < 1.0) which are formed in the land portions to extend inward in the radial direction of the tire allow removal of water between the tire and a snowy or icy road surface and the edges of the sipes allow cutting of the water film, thereby resulting in an improvement of the road contacting performance of the tire. Moreover, in the pneumatic tire, the elongated closed cells provided in the tread rubber serve as a water discharge passage up to the last stages of wear, and therefore, water discharge and removing effects can be constantly obtained efficiently. A protective layer made from resin prevents crushing of the elongated closed cells. Accordingly, even under the application of a heavy load, the water discharge and removal effect can be obtained. <IMAGE></p> |
