Abstract: A selected-length first, preferably tubular, rear member substantially subtending a side region of a vehicle just to the fore of the vehicle's rear wheel well has when mounted to the vehicle an integral extension that slides within, and strongly engages, another selected-length, forward, member that substantially subtends the remaining side region of the vehicle, extending so far as the vehicle's front wheel well. The two members together as are (i) individually selected in length, and (ii) slid together to a variable extent, jointly form a two-piece vehicular side, or nerf, bar that is precisely sized to the vehicle to which it is applied, strong, and suitably shipped by conventional land and air freight carriers. Lower levels of inventory are thus required to suit a wide range of vehicular applications.