The ornamental design for a tire tread, as shown and described.
FIG. 1 is a perspective view of a tire tread showing my new design, it being understood that the pattern repeats uniformly throughout the circumference of the tread;
FIG. 2 is a front elevation view thereof;
FIG. 3 is an enlarged fragmentary front elevation view thereof;
FIG. 4 is a right side elevation view thereof; and,
FIG. 5 is a left side elevation view thereof.
In the drawings, the broken lines defining the sidewall, inner bead and the peripheral boundary between the claimed tire tread and the unclaimed sidewall depict environmental subject matter that forms no part of the claimed design.