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 an enlarged, partial side view thereof;
FIG. 3 is a front view thereof; and,
FIG. 4 is a partial, enlarged front view thereof.
The remaining three-fourths portion of the tire partially shown in FIG. 2 is a repetition of the illustrated one-fourth portion, and the other side of the tire is identical. 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.