To provide a radial tire for motorcycles adaptable for a large-sized high-speed motorcycle and featuring high straight-forward traveling nature and strong abrasion resistance at its ground touching portion.

A carcass unit 14 is equipped with two carcass plies 16 and 17, and is structured so that the carcass cord has the angles of 65 degrees and 88 degrees with the circumference direction of a tire 10. The carcass ply 16 is designed so that its bead unit 13 is rolled up from the inner side in the diameter direction to the external side, and that the ply is overlapping symmetrically at a tread crown unit 18. Carcass plies 16 and 17 are tightened in the diameter direction at a band unit 15 and are thereby reinforced. The overlapping size Wo of the carcass ply 16 is set at 30% to 90% of the tread width size W. The carcass ply 17, meanwhile, is extended along a sidewall unit 12, up to the height (h). The height measurement (h) is set at 20% or more of the height measurement H of the sidewall unit 12.