The ornamental design for a tire tread, as shown and described.
FIG. 1 is a perspective view of a full tire including the tire tread of the present application;
FIG. 2 is a partial side view of a first side thereof;
FIG. 3 is a partial side view of a second side thereof; and,
FIG. 4 is a front view of the full tire.
The broken lines and the region therebetween defining the inner bead and the sidewall depict subject matter that forms no part of the claimed tire tread design, and are included for the purpose of illustrating the full tire. The tread pattern is understood to repeat throughout the circumference of the tire. The remainders of the side views repeat throughout the remainder of the circumference of the tire.