PNEUMATIC TIRE FOR ICE SNOW ROAD

摘要

PURPOSE:To improve the movement performance on an ice road without deteriorating the movement performance on a snow road by specifying the groove area rate of a tread pattern and snow traction index(STI) and specifying each numerical value relation of STI. CONSTITUTION:A tread pattern 1 is formed out of a number of blocks 4 consisting of a main groove 2 in the tire circumferential direction mm' and a subgroove 3 in the tire width direction. Further, each block 4 has kerves 5 in the tire width direction. In this case, the groove area rate of the tread pattern 1 is set to 30-40%. Further, the snow traction index(STI) shown by the equation I is set to 180-220. Further, the 220rhog and 672rhos in the equation I are set so as to satisfy the equation II.