Sway bars can dramatically effect handling by reducing body-roll which reduces weight transfer and tire camber change. Most cars are equipped with a sway bar at both ends. The ends of the car are connected to the lower suspension members while the center of the bar is connected to the chassis through bushings. During cornering, the outer suspension compresses while the inner extends. The ends of the car move in opposite directions and the bar twists. The stiffness of the bar acts against the suspension and opposes its movement, reducing body-roll. Increasing the diameter of a sway bar will increase its stiffness, which in turn increases the roll stiffness of that particular axle.

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-Arjay