The ornamental design for a tire tread, as shown and described.
FIG. 1 is a perspective view of a tire tread showing our design;
FIG. 2 is a front view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a fragmentary enlarged view showing the details of the tread thereof;
FIG. 7 is a section view taken along line 7-7 in FIG. 6;
FIG. 8 is a section view taken along line 8-8 in FIG. 6;
FIG. 9 is a section view taken along line 9-9 in FIG. 6; and,
FIG. 10 is a section view taken along line 10-10 in FIG. 6.
In the drawings, the dash/dot/dash broken lines adjacent to stippled surfaces depict the claim boundaries and form no part of the claim; all other broken lines depict environment and form no part of the claim.