The ornamental design for a tire tread, as shown and described.
FIG. 1 is a perspective view of the tire tread of our design;
FIG. 2 is a front elevation view of the tire tread of our design;
FIG. 3 is a side elevation view of the tire tread of our design;
FIG. 4 is a side elevation view of the tire tread of our design, taken from the opposite side of that shown in FIG. 3; and,
FIG. 5 is an enlarged, partial view of the tire tread of FIG. 1, as indicated by the break lines.
The dash-dot-dot-dash lines define the peripheral boundaries of the claim. The broken line disclosure in the drawings depicts environmental subject matter forming no part of the claimed design. The tread pattern repeats over the circumference of the tire.