The ornamental design for a tire tread, as shown and described.
FIG. 1 is a front, right, top perspective view of a tire tread showing my new design, it being understood that the pattern repeats uniformly throughout the circumference of the tire tread;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a right side elevational view thereof;
FIG. 4 is a left side elevational view thereof; and,
FIG. 5 is an enlarged fragmentary front elevational view showing the details of the tread portion thereof.
The broken line showing of the inner bead is included for the purpose of illustrating environment and forms no part of the claimed design.