Click on this SIMPLE VISUAL ANALYSIS link, to get an insight into of why the vehicle-occupants center of gravity should lay under the gray pyramid at the right:

And if you’re curious, you wanna know more, or you have a background in mechanics, do click on the links below. They present mathematical developments and calculations of the safety margins against rollover and forward tipping of 3-Wheelers:

Logic behind the  mathematical calculations of safety margin

Stability of 3-Wheelers with two driving-steering front wheels

Stability of 3-Wheelers with rear-engine and single-rear driving wheel

These mathematical analyses reveal problems of certain 3-Wheelers. Click on the following link to examine a less ‘mathematical’ but still very instructive summary:

Summary of safety margin calculations