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 front angled perspective view of the tire tread, 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 opposite side being identical thereto.
The broken lines showing the peripheral boundary and the inner bead are for the purpose of illustrating the boundary of the claim and form no part of the claimed design.