I claim the ornamental design for the tire tread design, as shown and described.
FIG. 1 is a perspective view of a tire tread, showing my new design;
FIG. 2 is a front view thereof; and,
FIG. 3 is a side view thereof.
In the drawings, the broken lines defining the two parallel circumferential grooves, 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 claimed design.