A tyre (1), the tread of which has an equatorial plane (5) and at least one raised element (4, 7), which has a longitudinal axis (4a) and respective lateral edges (4b, 4c) substantially parallel to the equatorial plane (5), and sipes (11a, 11b) crosswise to the longitudinal axis (4a); and wherein at least one sipe (11a; 11b) is Z-shaped and defined by three consecutive portions (14, 15, 16), a first and a third portion (14, 16) of which are end portions originating at respective lateral edges (4b, 4c; 4c, 4b), and a second portion (15) of which is an intermediate portion connected to the first portion (14) at a first point (17),which is located a first distance (D1) from the lateral edge (4b; 4c) from which the relevant firs portion (14) originates, and to the third portion (16) at a second point (18) located a second distance (D2) from the lateral edge (4b; 4c) from which the relevant firs portion (14) originates; the intermediate portion sloping with respect to the longitudinal axis (4a), and the second distance (D2) being less than the first distance (D1).