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 tread pattern repeats circumferentially throughout the outer circumference and shoulder of the tire, the opposite side perspective being identical thereto;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a side elevation view of the right side thereof, the left side elevation being identical thereto; and,
FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 2.
In the drawings, the broken lines depict environmental subject matter only and forms no part of the claimed design.