Patent attributes
This invention relates to a tire having an improved durability in the run-flat running without damaging the ride comfort in the usual running, and more particularly to a run-flat tire comprising a sidewall portion provided with a side reinforcing rubber layer having a crescent shape at section wherein a cord layer including a polyketone fiber cord satisfying the following conditions of the following equations (I) and (II):σ≧−0.01×E+1.2 (I)σ≧0.02 (II)[wherein σ is a thermal shrinkage stress at 177° C. (cN/dtex) and E is an elastic modulus at 25° C. under a load of 49 N (cN/dtex)] is disposed in at least a part of a region A ranging from a belt end to a maximum width part of a tire side portion and a region B ranging from a neighborhood of a bead core to a bead filler.
