Sway bars, or anti roll bars, are used mainly to reduce body roll. The vehicle's springs also reduce roll however, for a given spring rate they are only half as effective as sway bars. This means that by upgrading your sway bars, you can greatly reduce the roll of your vehicle making it corner flatter and increasing responsiveness, without increasing the harshness of your ride.
The handling of a vehicle is usually described as understeering, oversteering, or neutral. Understeer is when the front tires lose traction before the rear. This is how pretty much all vehicles are tuned from the factory. This is considered safe because if you were to enter a corner too quickly, the car will "plow" straight ahead and scrub off speed as the tires drag across the road creating friction. Once the vehicle slows enough, the front tires will regain traction and the vehicle will safely negotiate the corner. Oversteer is when the rear tires lose traction before the front. Enter a corner too quickly in a vehicle that oversteers and the rear end will slide which could cause the vehicle to spin. A vehicle tuned to oversteer is great if you are drifting on a closed course but is not a good handling quality to have on the street. A vehicle with neutral handling will be balanced such that the front and the rear tires, if pushed to the limit, will reach the limits of traction at the same time.
In addition to reducing body roll, another benefit of installing ADDCO sway bars is that the handling characteristics of your vehicle, when driven in a sporting manner, are greatly improved because we dial out the understeer to create neutral handling. The reason for this is that the stiffness of the front and rear bars in relation to each other, if chosen properly, can reduce the amount of understeer that manufacturers dial into to cars to almost nothing. Typically this is done by increasing the rear stiffness more than the front, essentially making the rear tires work harder to resist roll which helps to increase the amount of traction available from the front tires. The sizing has to be done with care though. If the rear bar is too stiff it can lead to oversteer.
To understand exactly how a sway bar works to resist roll, let's look at a single axle. Imagine the simplest sway bar shape which is a bar bent into a U shape. In this case one end of the U is attached to the left wheel, the other end of the U is attached to the right, and the center section runs laterally across the frame and is secured to the vehicle where the bar and the frame intersect so the frame and the center section are always parallel. As we watch a vehicle go around a corner from the outside we see the vehicle roll. If you look under the sheet metal though, what happens is the outside wheel is pushed up as the suspension compresses and the inside wheel moves down as the suspension droops. This displacement of the wheels twists the bar. The stiffer the bar, the harder it is to twist and the less the vehicle rolls. Its as simple as that.
Just about all vehicles benefit from upgraded sway bars. There some examples where they are almost mandatory. The first example is classic cars. Classic cars on modern tires (which have an incredible amount of traction compared to the tires they were supplied with originally) are subject to cornering forces they were never designed to experience from the factory. As a result, the amount of roll experienced during cornering is much greater than the original engineers ever intended. The second example is a truck that has been lifted or did not come from the factory with a sway bar. Lifted trucks raise the center of gravity of the vehicle which increases the amount of roll and needs to be controlled. Finally, sometimes bean counters get their way and as a result some trucks did not come from the factory with rear sway bars. These vehicles also benefit greatly from a set of ADDCO bars, especially if driven daily.
In real world use ADDCO sway bars in addition to reducing body roll, also improve handling. They make a pickup truck handle like a SUV, a SUV handle like a sedan, a sedan handle like a sports car, and a sports car handle like a race car! Try a set today and experience it yourself.