The ornamental design for a tire tread, as shown and described.
FIG. 1 is a perspective view of a tire, it being understood that the tread pattern repeats circumferentially and uniformly throughout the outer circumference and shoulder area of the tire, where the opposite perspective view being an identical image thereto; and,
FIG. 2 is a front elevation view thereof.
In the drawing, the shading represents the recessed groove portions of the tire tread having a depth. The broken line disclosure of the tire side wall and bead areas are for illustrative purposes only and form no part of the claimed design.