The ornamental design for a motorcycle tire, as shown and described.
FIG. 1 is a front-perspective view of a motorcycle tire of my new design;
FIG. 2 is a front view of my new design, the top and bottom views being identical thereto, the rear view being identical in configuration, but inverted;
FIG. 3 is a right-side view of my new design, the left-side view being a mirror image thereof; and,
FIG. 4 is a close-up view of the tread pattern of my new design.