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 repeats uniformly throughout the circumference of the tread;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a right side elevational view thereof; the other side being a mirror image thereof; and,
FIG. 4 is an enlarged fragmentary front elevational view thereof.
In the drawings, the broken lines defining the sidewall, inner bead and the peripheral boundary between the tire tread and the sidewall in FIGS. 1 through 4 are for illustrative purposes only and form no part of the claimed design.