Pneumatic tire tread having groove with peaks and valleys

A tread for a pneumatic tire, an external surface of the tread having at least one groove for enclosing and channeling water during use of the tire on wet pavement, the groove having at least two surfaces defining a channel, the surfaces including two side surfaces, the respective side surfaces beginning at the external surface of the tread and extending radially inwardly toward an axis of rotation of the tire, the two side surfaces either intersecting with one another or with a bottom surface, the groove having a depth defined by an average distance from the external surface of the bead to the intersection of the two side surfaces or to the bottom surface, a median plane bisecting the channel formed by the respective surfaces of the groove, the groove having a width defined by twice an average distance from the median plane to a respective side surface, the tread being characterized by:

• a series of peaks and valleys located on both side surfaces of the groove, an imaginary line or arc bissecting the channel formed by the respective surfaces of the groove, extending along the length of the channel, and being located on the median plane within the depth of the groove, at least half of the valleys following imaginary lines that are skewed with respect to the median plane line or arc by an angle or angles in the range of from 45 degrees to 90 degrees, each peak having a maximum depth of 15% of the groove width and a minimum depth of at least 5% of the groove width, the depth being defined as the average distance from the peak to the valley, the series of peaks and valleys having a pitch between respective peaks of less than 40 % of the groove width, when water flows through the groove, the series of peaks and valleys disrupt eddies or vortices along the side surfaces of the groove decreasing skin friction drag, each valley extending continuously from one side surface of the groove to the other side surface of the groove.