A three-wheeled truck is apt to turn over, compared with an ordinary truck or car. Therefore its designers must be especially careful of its stability, which is shown by the overturn angle on the rest. This essay discusses the theoretical effects of wheel-base, tread and centre of gravity on the overturn angle and describes several instances. Moreover, when it is running in a circle, it turns over if its speed becomes very large. This essay shows the relation between the critical speed and the turning radius to insure safe running and adds several instances.
