Vehicles often experience "roll" while turning or during an increase in the camber of road. A vehicle's speed, height, center of gravity and weight are a few factors affecting to what degree it will experience roll. Minimizing roll and maintaining stability are critical to both performance and safety. A vehicle's shocks and springs, or struts, largely counteract vertical forces. These suspension components, alone, are not best suited to counteract a vehicle's roll or sway.
Anti-rolls bars are often referred to as sway bars, stabilizers or roll bars. Anti-roll bars should not be confused with "roll bars" that are installed in race or street cars and largely consist of steel tubing bent and welded to form a protective cage for a driver.
Anti-roll bars are u-shaped bars constructed typically from steel that connect a left and right side wheel with two points on a vehicle's chassis. A vehicle is normally equipped with two anti-roll bars; one is usually located near the front end housing and another can be found near the rear end housing.
Anti-roll bars are attached to the vehicle's chassis, but the device can rotate within its mounts without physically twisting and becoming stiffer. When the left and right suspension travel (vertically) in equal amounts, a vehicle is not experiencing roll. In this case, the anti-roll bar does not "twist" but rotates in place and stays in a neutral state. Only when there is a difference in suspension travel between right and left sides does the anti-roll bar begin to twist. Because right and left sides are linked by this devices, the twisting motion of the anti-roll bar, which is known as torsion, helps minimize the vehicle from experiencing pronounced roll.
The anti-roll bar reduces body roll by countering a vehicle's lean using torsion, or twisting. The difference in right and left side suspension travel or position puts a twisting force on the anti-roll bar. This device is usually constructed of steel or tough alloys to handle such high loads so frequently. As the diameter of the anti-roll bar increases, more force is required to twist the device. Thus, an increased diameter anti-roll bar would be well suited to heavier vehicles or in high-force applications such as racing.
