| 摘要 |
PURPOSE:To improve performance on ice like braking, climbing running, lateral slide-proof capacities while keeping the uneven abrasion-resistance. CONSTITUTION:A tread 2 is divided into the central part 4 and side parts 5 by two chief vertical grooves 3. In the central part, a central block BC provided with a siping 8 with a central auxiliary vertical groove 6 and a lateral groove 7, is formed and in the side parts, inner and outer blocks BI, BO provide with sipings 12 at the inner and outer sides of an auxiliary vertical groove 10, are formed. The ratio of the sum total SIGMAXi of circumferential length of the tire at the inner and outer block side to the bloc area Sx, SIGMAXi/Sx, is made (3.5-7.5)X10<-2>1/mm, and the ratio of the sum total SIGMAYi of the length in the axial direction of the central siping of the central block to the block area Sy, SIGMAYiSy, is made (8.5-12.5)X10<-2>1/mm. |
