The ornamental design for rack sides, as shown and described.
FIG. 1 is a perspective view of rack sides showing our new design;
FIG. 2 is a another perspective view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a front elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a right side elevational view thereof;
FIG. 7 is a top plan view thereof;
FIG. 8 is a bottom plan view thereof;
FIG. 9 is a rear elevational view of a second embodiment of rack sides;
FIG. 10 is a front elevational view of FIG. 9;
FIG. 11 is a left side elevational view of FIG. 9; and,
FIG. 12 is a right side elevational view thereof.
The broken lines, which define the bounds of the claimed design, form no part thereof. The broken lines showing environment is for illustrative purpose and forms no part of the claimed design.