The ornamental design for a tiresidewall, as shown and described.
FIG. 1 is a perspective view of the tire sidewall of our design;
FIG. 2 is a side elevation view of the tire sidewall of our design;
FIG. 3 is a front elevation view of the tire sidewall of our design; and,
FIG. 4 is an enlarged, partial view of FIG. 1.
In the drawings, the broken lines depict environmental subject matter that forms no part of the claimed design. The dash-dot lines represent the peripheral boundary of the claimed design. The pattern is understood to repeat uniformly over the annular area of the tire sidewall.