Tyre comprising a tread band on which are defined: - a plurality of grooves , - a plurality of blocks delimited by said plurality of grooves , - a plurality of three-dimensional sipes formed in at least one block of said plurality of blocks, said three-dimensional sipes being open on a tread surface that is radially external to said tread band and extending in a direction that is incident to a forward direction (F) defined on said tread surface, wherein each three-dimensional sipe of said plurality of sipes separates said at least one block into: - a first block portion comprising a first surface extending along a reference plane (X) that is incident to said tread surface , and - a second block portion comprising a second surface extending along a reference plane (X') that is incident to said tread surface , said second surface being opposite said first surface , wherein: - between said first block portion and said second block portion a plurality of male/female couplings are provided, - all the male/female couplings between said first block portion and said second block portion are formed by a plurality of protuberances that are formed on said first surface and extend from said reference plane (X) towards said second block portion , and by a plurality of recesses formed in said second surface and extending from said reference plane (X') away from said first block portion , - said protuberances provided on said first surface have an apex that is at a distance from said tread surface of a measure of no more than 40 % of the depth of said three-dimensional sipe measured at said apex , characterized in that - said protuberances have a pyramidal shape having a quadrilateral plan having a first and a second pair of adjacent sides , which are substantially equal to one another, and a longer diagonal and a shorter diagonal that are perpendicular to one another. - a plurality of grooves , - a plurality of blocks delimited by said plurality of grooves , - a plurality of three-dimensional sipes formed in at least one block of said plurality of blocks, said three-dimensional sipes being open on a tread surface that is radially external to said tread band and extending in a direction that is incident to a forward direction (F) defined on said tread surface, - a first block portion comprising a first surface extending along a reference plane (X) that is incident to said tread surface , and - a second block portion comprising a second surface extending along a reference plane (X') that is incident to said tread surface , said second surface being opposite said first surface , - between said first block portion and said second block portion a plurality of male/female couplings are provided, - all the male/female couplings between said first block portion and said second block portion are formed by a plurality of protuberances that are formed on said first surface and extend from said reference plane (X) towards said second block portion , and by a plurality of recesses formed in said second surface and extending from said reference plane (X') away from said first block portion , - said protuberances provided on said first surface have an apex that is at a distance from said tread surface of a measure of no more than 40 % of the depth of said three-dimensional sipe measured at said apex , - said protuberances have a pyramidal shape having a quadrilateral plan having a first and a second pair of adjacent sides , which are substantially equal to one another, and a longer diagonal and a shorter diagonal that are perpendicular to one another. <EOS>