| 摘要 |
PURPOSE:To improve a vehicle offset-leaning without sacrifice of driving stability performance and ride comfortability so as to improve straight driving performance by specifying belt rigidity index and also bead part rigidity index. CONSTITUTION:A pneumatic radial tire 1 is provided with a carcass 6 which passes through a side wall part 3 from a tread part 2 and returns at the bead core 5 of a bead part 4, a belt 7 which is arranged outside the carcass 6 in a radial direction of the carcass 6 and inside the above tread part 2, and an appropriate bead reinforcement layer 9 at the bead part 4. In this case, belt rigidity index (x) which is determined by the following formula (1) is set at 1.0-4.5, and bead part rigidity index (y) which is determined by the following formula (2) is set at 4.6-5.2. x=Bw<2>.Bm.10<-5>/sintheta deg....(1), y= Bl<2>.Bh.Fg.C.F.10<-6>...(2). |
