The ornamental design for a tyreinflator/deflator, as shown and described.
FIG. 1 is a perspective view of a tyre inflator/deflator of the present invention;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a right side view thereof; and,
FIG. 7 is a left side view thereof.
The broken lines in FIGS. 3 and 5 are included for the purpose of illustrating portions of the tyre inflator/deflator that form no part of the claimed design.