Pneumatic radial tire

A pneumatic radial tire comprising:

• an annular tread member;
• a pair of sidewalls extending from opposite ends of the tread portion in the radial direction of the tire;
• a pair of bead members provided at the ends of the sidewalls and each of which has a bead core embedded therein and a pair of bead apexes of a gradually reducing thickness toward a maximum tire width;
• a carcass layer including carcass cords arranged in the radial direction of the tire, said carcass layer extending through both sidewall portions and said tread member;
• breaker layers arranged in the external radial part of the carcass layer,
• wherein said carcass layer is formed of a single ply of carcass cords that are folded around said bead core at each end of the carcass in such a way that turned-up ends of the carcass layer extend to a position beneath said breaker layer within a range defined by a width of said breaker layer;
• and
• a rubber layer being provided between said carcass layer and the turned-up ends of said carcass layer in such a way that said rubber layer extends from below said breaker layer and terminates at an upper end of a respective bead apex.