The ornamental design for a tiresidewall, as shown and described.
FIG. 1 is a front elevational view of a tire sidewall showing my new design; and,
FIG. 2 is a front elevational view of a second embodiment thereof showing the disclaimed portions of FIG. 1 in solid lines.
In the drawings, the broken lines showing of the tire tread, inner bead and the peripheral boundary between the tire tread and the sidewall in FIG. 1 depict environmental subject matter and form no part of the claim.