The ornamental design for a tire tread, as shown and described.
FIG. 1 is a front elevational view of a tire tread showing the new design on the face of a tire; and,
FIG. 2 is a perspective view thereof.
The broken lines in both figures are for illustrative purposes only; they show the relation of the claimed tire tread to the remaining portions of the tire and are not claimed as part of the design. The broken lines contained in the individual lugs are for illustration only and are not claimed as part of the design. The claimed design is only visible on the exterior face of the tire and consists of a repeating pattern which appears identical no matter which section of the tire face is viewed.