The ornamental design for a tire tread, as shown and described.
FIG. 1 is a perspective view of a tire tread of the present application;
FIG. 2 is a front view thereof;
FIG. 3 is side view thereof;
FIG. 4 is an enlarged partial perspective view thereof; and,
FIG. 5 is an enlarged partial front view thereof.
The broken lines and the region between the inner bead and the sidewall depict subject matter that forms no part of the claimed tire tread design, and is included for the purpose of illustrating the full tire. The tread pattern is understood to repeat throughout the circumference of the tire. The other side view is identical to the illustrated side view of FIG. 2.