wheel tread

the distance between the longitudinal axes of the impressions (on the road surface) of the right and left wheels of a single axle of a motor vehicle; with the double rear wheels of trucks and buses, the distance between the middles of the impressions of the right and left double wheels. Since in a majority of instances the tread of the axles differs for motor vehicles with front and rear (multiple) axles, the various treads are designated separately.