Stability Triangle

However, if the center of gravity shifts outside the stability triangle, the lift truck will tip over. The center of gravity within a lift truck can be moved by: 
* Traveling with an elevated load;
* Trying to carry too heavy a load;
* Trying to turn the lift truck while it is moving too fast; 
* Operating the lift truck on a hill or incline;
* Starting or stopping too fast;
* The jerky operation of the hydraulic system.