Pneumatic tire

摘要

At least one reinforcing rubber layer is provided in the part of each of two side wall portions which is on the outer side of a carcass layer so as to improve the steering stability while maintaining the durability of belt layers at a level equal to that of conventional belt layers without causing an increase in the weight of the tire. The outer circumferential end portions of the reinforcing rubber layers extend to positions in which they are disposed between the end portions of the innermost belt layer and the corresponding portions of the carcass layer, while the inner circumferential end portions of these rubber layers extend inward in the radial direction of the tire so as to overlap the bead fillers in positions on the outer sides of the end portions of the carcass layer in the widthwise direction of the tire. A 100% modulus at 100 DEG C of the rubber constituting the reinforcing rubber layers is not higher than that of the rubber of the belt layers, and a dynamic elastic modulus at 20 DEG C of the former rubber in the range of 10-40 MPa. The thickness of the portions of the reinforcing rubber layers which are between the edges of the innermost belt layer and the outer circumferential ends of the bead fillers is set securely to not less than 1.00 mm, and the thickness of the parts of the side wall portions which are on the tire outer sides of the reinforcing rubber layers also not less than 1.00 mm.