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 front view thereof;
FIG. 3 is a side view thereof; and,
FIG. 4 is an enlarged partial front view thereof.
The broken line showing of the sidewall, inner bead, and the peripheral boundary between the tire tread and the sidewall is included for the purpose of illustrating environment and forms no part of the claim.