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 is repeated throughout the circumference of the tire, the opposite side being substantially the same as that illustrated; and,
FIG. 2 is a enlarged fragmentary view of the tread pattern of the tire tread of our design as shown in FIG. 1.
The broken line showing of a tire inner bead and sidewall is for illustrative purposes only and forms no part of the claimed design.