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 is repeated throughout the circumference of the tire, the opposite side perspective being identical thereto;
FIG. 2 is a front elevation view thereof, the rear elevation being identical thereto;
FIG. 3 is a side elevation view thereof, the opposite side elevation being identical thereto; and,
FIG. 4 is a section view of said tire tread taken along line 4-4 shown in FIG. 2.
In the drawings, the broken lines depict environmental subject matter only and form no part of the claimed design. The dot and dashed lines define the bounds of the claimed design and form no part thereof.