The ornamental design for a tire tread, as shown and described.
FIG. 1 is a perspective view of a tire tread showing our new design it
being understood that the pattern is repeated throughout the circumference
thereof;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a side elevational view thereof; and,
FIG. 4 is an enlarged fragmentary front view thereof.