TYRE CARCASS PLY FOR TWO-WHEELED VEHICLES

摘要

The objective is satisfactory motorbike stability both in a straight line at high speed and in curves at high camber angles. Tyre (1) for a motorized two-wheeled vehicle of the motorcycle type, comprising: a tread (2) connected by two sidewalls (3) to two beads (4); a crown ply (5) comprising at least one crown layer (51); and a carcass ply (6) comprising at least one turned-up carcass layer (61), said turned-up carcass layer (61) comprising mutually parallel reinforcements and being wound around a bead wire (7), within each bead, from the inside toward the outside of the tyre, in order to form a turn-up (8) having a free end (E). The turned-up carcass layer (61) comprises a crown-region portion (611) and a lateral portion (612), the crown-region portion (611) extending axially between a first and a second end (E1, E'1), which are symmetric with respect to the equatorial plane (P), the lateral portion (612) extending radially inwards, from a first end (E2) as far as a second end (E3). The reinforcements in the crown-region portion (611) make, with the circumferential direction (X), a substantially constant angle equal at least to 65°. The reinforcements in the lateral portion (612) make, with the circumferential direction (X), an angle that increases, from the first end (E2) to the second end (E3), from an angle smaller than at least 5° to the substantially constant angle, formed by the reinforcements of the crown-region portion (611). The reinforcements in the turn-up (8) make, with the circumferential direction (X), an angle equal in terms of absolute value but with opposite sign, to the angle formed by the reinforcements in the lateral portion (612).