FIG. 1 is a perspective view of the tire gauge; FIG. 2 is a perspective view of the tire gauge; FIG. 3 is a front view of the tire gauge; FIG. 4 is a back view of the tire gauge; FIG. 5 is a side view of the tire gauge; FIG. 6 is a side view of the tire gauge; FIG. 7 is a top view of the tire gauge; and, FIG. 8 is a bottom view of the tire gauge. The broken line showing is for illustrative purposes only and forms no part of the claimed design.