A mechanical gauge includes a stock panel with a first measurement scale, and a slide movably arranged relative to the stock panel. The first measurement scale has a series of marks spaced apart at regular intervals within a region of interest. The slide includes a second measurement scale adapted to selectively overlie the first measurement scale within the region of interest. The second measurement scale has a second series of marks spaced apart at regular intervals corresponding to the first series of marks of the first measurement scale. An elongated measurement probe is affixed to the slide and adapted for selectively extending into a groove formed in the tread of the vehicle tire.