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 a tread pattern is repeated over the outer circumference and shoulder of a tire, the opposite side being substantially an inverted mirror image of that illustrated; and,
FIG. 2 is a enlarged fragmentary front elevation view of the tread pattern of FIG. 1 showing our new design for the tire tread.
The broken line showing of a tire sidewall and inner bead is for illustrative purposes only and forms no part of the claimed design.