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, it being understood that the tread pattern repeats circumferentially throughout the outer circumference and shoulder of the tire, the opposite side perspective being identical thereto;
FIG. 2 is a front elevation view thereof; and,
FIG. 3 is a side elevation view of the right side thereof, the left side elevation being identical thereto.
In the drawings, the broken lines defining the sidewall, inner bead and the peripheral boundary between the claimed tire tread and the unclaimed sidewall depict environmental subject matter that forms no part of the claim.