Patent ID: 7793695

Claim:
A pneumatic radial tire for a motorcycle, having a tread portion formed in a shape of ring, a pair of sidewall portions disposed inside from both sides of said tread portion in a tire radial direction and a bead portion continuing on the inside of said sidewall portions in the tire radial direction, which comprises: a carcass ply composed of at least one layer of textile cords to reinforce those respective portions mutually between bead cores respectively embedded in said bead portions; and at least one layer of mono-spiral belt for reinforcing said tread portion around said carcass ply: wherein; said mono-spiral belt includes steel cords whose tensile break strength is 147 MPa or more; a value Tc of a number of driven cords of said mono-spiral cords (per 25 mm in width) at an equator of the tire and a value Ts at shoulder parts thereof meet requirements of 17≦Tc≦24 and 0.6≦Ts/Tc≦0.9; a disposed width BW of the mono-spiral cords meets a requirement of 0.6≦BW/TW≦1.0 with respect to a total width TW of the crown portion in a no-load state in which the belt is attached to a standard rim and a standard inner pressure is filled; at least one layer of a textile-reinforcing layer having a tensile break strength of 98 MPa or higher is disposed at both ends of the mono-spiral belt; and an overlap of the mono-spiral belt with the textile-reinforcing layer is 4 to 10 times of a diameter D of the steel cords of the mono-spiral belt.