The ornamental design for a tire tread, as shown and described.
FIG. 1 is a side perspective view of a tire tread showing my new design, it being understood that the tread pattern is repeated throughout the circumference of the tire tread, the opposite side being the same as that shown;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a side elevational view of the right side thereof, the opposite side being a mirror image thereof; and,
FIG. 4 is an enlarged fragmentary front elevational view thereof.
The broken lines defining the tire sidewall, inner bead, and the peripheral boundary between the claimed tire tread and sidewall are for illustrative purposes only and form no part of the claimed design.