PURPOSE: To improve the stability of steering etc., by providing a bead apex at a part surrounded by the body and curved-back end of a carcass and by providing a bead reinforcing layer extending from the bottom of a bead to a sidewall.

CONSTITUTION: Both the ends of a reinforcing ply of cords oriented at about 75 to 95° to the equator surface of a tire, are anchored to bead wires 4 so that a toroidal carcass 3 is provided. The crown part of the carcass 3 is reinforced by a belt layer 5. A bead apex 9, the thickness of which gradually decreases from the top of the bead wire 4 toward the sidewall, is provided at a part surrounded by the body and curved-back end of the carcass 3. A bead reinforcing layer 10 of fiber cords extending from the bottom of the bead to the sidewall is also provided at the part surrounded by the carcass 3. The width TW of the tread is set at 50W58% of the maximum width SW of the tire.