The ornamental design for a tire tread, as shown and described.
FIG. 1 is a perspective view of a tire tread showing my new design, it being understood that the pattern is repeated uniformly throughout the circumference of the tread.
FIG. 2 is a front elevational view thereof; the rear elevational view thereof, top plan view thereof, and bottom plan view thereof are identical to the front elevational view.
FIG. 3 is a left side view thereof; the right side view is identical to the left side perspective view; and,
FIG. 4 is an enlarged fragmentary view from upper 4-4 to lower 4-4 in FIG. 2.
The broken lines illustrate environmental subject matter only and form no part of the claimed design. The dash-dot-dash broken lines define the boundary of the tire tread and form no part of the claimed design.