PURPOSE: To prevent damage on the road surface during running on the general road surface as well as to improve friction performance when running on the surface of frozen road in such a way that spike pins which are composed of vulcanized rubber which has a characteristic to change the hardness according to its temperatures are saliently provided on the tread of tire.
CONSTITUTION: The desired dpiked tire can be obtained in such a way that a plurality of hole parts 11 are formed on the surface 2 of the tread part 1 of a pneumatic tire, and spike pins 12 are driven into the hole parts 11 so as to have their upper faces protruded from the tread surface 2. Then, said spike pins 12 is formed of a valcanized rubber faving a JIS hardness to be higher 80° at the tepmerature of the atmosphere below 0°C, and below 70°C at the temperature atmosphere below 30°C. Such a rubber material is made of a rubber compound in which for example, zinc oxide, strearic acid. carbon black and other compunding agents are compunded on high styrene SBR at the determined proportion.
OCHIAI TOSHIO
MIFUJI KAZUTOMO
MISAWA MAKOTO
