The ornamental design for a tire tread, as shown and described.
FIG. 1 is a perspective view of the 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 view of the tire tread thereof.
FIG. 3 is a side view of the tire tread thereof; the opposite side view being identical thereto; and,
FIG. 4 is a partial close up front view thereof.
In the drawings, the broken lines defining the sidewall, inner bead and the peripheral boundary between the tire tread and the sidewall are for illustrative purposes only and form no part of the claimed design.