The ornamental design for a tire tread, as shown and described.
FIG. 1 is a front perspective view of the tire tread showing our design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a first side view thereof;
FIG. 5 is a second side view thereof;
FIG. 6 is a fragmentary enlarged view thereof; and,
FIG. 7 is a cross-sectional view thereof taken along line 7-7 in FIG. 6.
The dash-dash broken lines are used to show unclaimed environment, and thus form no part of the claimed design. The dash-dot-dash lines are used to show a boundary between claimed and unclaimed subject matter.