The ornamental design for a tire tread, as shown and described.
FIG. 1 is a front elevational view of the tire tread, 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 fragmentary perspective view of the tire tread shown on a reduced scale from FIG. 1, it being understood that the tread pattern is repeated throughout the circumference of the tire tread; and,
FIG. 3 is a side elevational view of the right side of the tire tread.
The broken lines in FIGS. 2 and 3 form the boundary of the claim, with the broken lines themselves forming no part of the claimed design.