| 摘要 |
PURPOSE:To reconcile performance on the ice and abrasion resistance by limiting an average foam diameter of a foaming rubber layer of a tread part, and setting the area average diameter standard deviation not less than a prescribed value. CONSTITUTION:A pneumatic tire 1 has a tread 3 to cover mutual shoulders 4 of a crown part 2a of a tire case 2. A foaming rubber layer having independent foams on which an average diameter of foams observed in a cross section is 5 to 50mum and an area average diameter standard deviation S.DAREA expressed by an expression I is not less than 25mum, is used as a tread part 3. Herein, (di) represents a foam diameter. A bar (d) is expressed by an expression II, and (ni) is the number of foams. Rsi represents a frequency (the area ratio), and is expressed by an expression III. Since the average foam diameter and the area average diameter standard deviation are limited in this way, performance on the ice and abrasion resistance can be reconciled with each other. |
