The ornamental design for a tire tread, as shown and described.
FIG. 1 is a front perspective view of a new design for a tire tread, it being understood that the pattern repeats uniformly around the circumference of the tread;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a left side elevation view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is an enlarged left side elevation view taken along box 5 of FIG. 3;
FIG. 6 is a cross-sectional elevation view taken on lines 6-6 of FIG. 2; and,
FIG. 7 is an enlarged perspective view taken along circle 7 of FIG. 6.
In the drawings, the broken lines defining the sidewall, inner bead and the peripheral boundary between the claimed tire tread and the unclaimed sidewall depict environmental subject matter that forms no part of the claimed design.