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 side view of the inside of the tire;
FIG. 3 is a side view of the outside of the tire;
FIG. 4 is a front view thereof; and,
FIG. 5 is partial, enlarged front view thereof.
The remaining portion of the tire tread partially shown in FIG. 5 is a repetition of the illustrated portion. The broken line showings of the sidewall, inner bead, and the peripheral boundary between the tire tread and the sidewall, are included for the purpose of illustrating environment and form no part of the claim.