The ornamental design for a tire tread, as shown and described.
FIG. 1 is a perspective view of a tire tread showing our new 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 front view;
FIG. 7 is an end view taken along line 7-7 in FIG. 6; and,
FIG. 8 is an end view taken along line 8-8 in FIG. 6.
Broken lines shown in the drawings are intended to show portions of the tire tread that are not being claimed, and thus illustrative purpose only and form no part of the claimed design. The dash-dot-dash broken lines are used to show the boundary between unclaimed and claimed subject matter, and thus form no part of the claimed design. The light stippled surface shading represents the surface of the tire tread, and the dark stippled surface shading represents the recessed portion of the tread grooves, having the depth as shown in FIGS. 7 and 8.