 The producers were only able to locate four of the many Sherman  tanks seen on the screen. The rest were plastic molds set on top of  88" Landrovers. VW Beetle chassis were used for German Kubelwagens.  The tank treads didnt reach the ground, but the film is edited so  that this isnt noticeable (except in the section after  Elliott Gould (qv) cries "Roll the fuckers / Roll em fellas"  there are shots of the tanks rolling over the bridge. One tank is  seen silhouetted against the background and its tracks are clearly  not moving as fast as they should be if the tank where real.)