Radial tyre.

摘要

A passenger car radial tyre having a tread surface comprising in cross section an inner arc portion (21) which has a radius of curvature of R1 and outer arc portion (22) which are smoothly connected to the said inner arc portion in such a manner as to constitute the shoulder portions of the tyre tread surface and which have a radius of curvature R2 wherein: (a) the radius of curvature R1 is 1.4 to 2.5 times the sectional width W (b) the radius of curvature R2 is 1.5 - 2.5 times R1 and (c) the inner arc portion (21) and the outer arc portions (22) are connected to one another by junctions (24) which are spaced from the equator surface (C) of the tyre by distance L which is 0.08 -0.2 times the sectional width W of the tyre. The resultant tyre exhibits reduced vibration forces from the tyre and transmitted to the vehicle particularly in the shoulders and reduces the vertical rigidity in the shoulder portions so that the tyre is of a lower noise characteristic and transmits lower noise from the road to the tyre without affecting wear or running stability.