here is some illustrated information on your question
Forklifts have a "stability triangle". The sides of the triangle as shown in the illustration are formed by the center of each front wheel and the center of the rear wheel or at the center of the axle if there are two rear wheels.
A vertical line extending from the center of gravity of the vehicle-load combination must be inside of the stability triangle to prevent the forklift from tipping forward, falling sideways or dropping its load.
Let me know if you have any more questions like this im a JJ keller safety trainer.