Center of Gravity—Why Rollovers Happen (animation) - A particular object's center of gravity—in this case an SUV—will always be contained within the geometric confines of that vehicle as it's oriented in space relative to the pull of gravity. If there's a change in a vehicle's spatial orientation due to the imposition of some external force, the vehicle's center of gravity will shift from its original position as long as that external force persists. That means that the tires, which had supported a vehicle's center of gravity, begin to lose their usefulness as supporting structures relative to the pull of gravity. As a result, the vehicle seeks a new structural support relative to the pull of gravity, like its side or roof. If this change happens fast enough, the vehicle will not only fall over: it will roll.