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.
In the drawings, the broken line disclosure depicts environmental subject matter and forms no part of the claimed design. The dash-dot-dot-dash lines represent the peripheral boundary of the claim.