Tire tread comprising complex grooves and incisions

A tire tread comprising:

• a tread surface,
• this tread being provided with a tread pattern formed by at least two longitudinally oriented grooves, the tread pattern having a maximum tread pattern depth Hm,
• at least one of the longitudinally oriented grooves, known as a complex groove, comprising alternately external cavities that open onto the tread surface in a new state and internal cavities that are hidden within the thickness of the tread in the new state,
• the external cavities of each complex groove opening onto the tread surface when in the new state with a contour having a mean longitudinal length Lm, and furthest apart end points A and B, the external cavities having a depth at least equal to 0.9 Hm,
• the external cavities of each complex groove being separated by internal cavities having a mean longitudinal length Li, Li being at least equal to 0.5*Lm and at most equal to 2*Lm,
• this tread comprising at least one rib oriented in the longitudinal direction of the tread and delimited by at least one of said complex grooves, the rib comprising transverse sipes-that is to say sipes with an orientation equal to or greater than 45 degrees to the longitudinal direction, made at a mean spacing Pm, the depth of these transverse sipes being at least equal to the depth 0.1*Hm,
• wherein the mean spacing Pm of the transverse sipes is at most equal to the mean longitudinal length Lm of the external cavities.