The ornamental design for a tire tread, as shown and described.
FIG. 1 is a perspective view of a tire tread showing my new design, it being understood that the tread pattern repeats uniformly throughout the outer circumference and shoulder of a tire, the opposite side perspective view being identical thereto; and,
FIG. 2 is an enlarged fragmentary front elevation view of the tire tread thereof of FIG. 1.
The broken line disclosure of the tire sidewall and inner bead is for illustrative purposes only and forms no part of the claimed design.