The ornamental design for a tire tread, as shown and described.
FIG. 1 is a perspective view of a tire tread showing my new design, it being understood that the pattern is repeated uniformly throughout the circumference of the tread;
FIG. 2 is a front elevational view thereof; a top plan view thereof is identical to the front elevational view; a bottom plan view thereof is identical to the front elevational view; and a rear elevational view is identical to the front elevational view;
FIG. 3 is a left side view thereof; and a right side view is identical to the left side view; and,
FIG. 4 is an enlarged fragmentary view of the upper 4-4 to lower 4-4 in FIG. 2.
The broken lines illustrate environmental subject matter only and form no part of the claimed design. The dash-dot-dash broken lines define the boundary of the tire tread and form no part of the claimed design. Surface shading lines and stippling in the drawings depict the character or contour of the surfaces represented and form no part of the claimed design.