The ornamental design for a tire tread, as shown and described.
FIG. 1 is a perspective view of a first embodiment of a tire tread, it being understood that the tread pattern repeats uniformly throughout the circumference of the tire.
FIG. 2 is a front elevation view thereof.
FIG. 3 is a left side elevation view thereof; and,
FIG. 4 is an enlarged fragmentary view thereof.
The broken lines shown in the drawings are for the purpose of showing environmental structure only and form no part of the claimed design.