The ornamental design of a trailerfender for tandemwheels, as shown and described.
FIG. 1 is a perspective view of the rear fender of a pair of fenders for a pair of tandem wheels of a trailer;
FIG. 2 is a top view thereof;
FIG. 3 is a bottom view thereof;
FIG. 4 is an outside view thereof;
FIG. 5 is an inside view thereof;
FIG. 6 is a front view thereof;
FIG. 7 is a rear view thereof; and,
FIG. 8 is a perspective view of a pair of trailer fenders for a tandem trailer, with the left portion of the figure being identical to the fender of FIG. 1, and the right portion thereof being a mirror image thereof, with the right portion illustrated in broken lines, with the broken lines included for illustrative purposes, and which form no part of the claimed design.