Controlling body roll is paramount in performance driving. Sway bars are a “must-have” to accomplish this. Image www.chevelles.com

Choosing a sway bar that will make an improvement to your car’s handling can be a daunting task. Depending on what you are actually trying to accomplish, replacing the front sway bar will change certain handling characteristics, while replacing the rear sway bar will change others. When choosing a sway bar, it is definitely not a one-size-fits-all situation. Not only do sway bars come in different sizes and shapes, but their construction varies as well. They are available in both hollow tube and solid-tube construction. The world of vehicle dynamics and the science of automotive suspension operation can get very complicated, and is many times, a challenging obstacle to tackle. Luckily, we found that Hellwig can help guide you through choosing the correct sway bar for both your car and driving style. This will hopefully simplify the process of upgrading your car’s suspension.

Believe it or not, a sway bar is a simple suspension component. When you drive into a corner, the outside of the vehicle will squat while the inside will lift and unload. This body roll is what we want to reduce in a performance vehicle. When body roll occurs, you are taking weight from the inside tire and applying it to the outside. When this happens, the car is using only one front tire to turn instead of both. A sway bar acts as a torsion bar that transfers load (force) from one side of the car to the other by connecting the left and right suspension components. This distributes the turning forces more evenly across both sides of the vehicle and helps it stay flat when cornering.

During certain driving conditions, a rear-wheel-drive car will inherently allow the rear of the car to want to “come around” the front of the car (slide), and cause oversteer. By increasing the stiffness of the front sway bar, you can decrease oversteer when cornering. This is because a stiffer front bar reduces body roll by diagonally transferring more weight to the rear tires, which actually increases understeer. This is called Tire Lateral Load Transfer Distribution, which is the measurement of the front-to-rear balance of how lateral load is transferred when cornering. In basic terms, TLLTD is understeer or oversteer. Now that we know a sway bar will limit body roll, what might not be obvious is the effect of a sway bar on TLLTD (understeer and oversteer).

Some high-end performance sway bars from Hellwig are even adjustable. Image: www.streetmusclemag.com

Since a stiffer sway bar has a greater torsional resistance, and allows less deflection, it will transfer any side-to-side energy at a faster rate than one with less torsional stiffness. As the rate of lateral load-transfer increases, so do the demands that are then placed upon the tire. This means that if we install a stiffer sway bar in the front of the car, then we increase the distribution of lateral load-transfer toward the front tires. This increases the front TLLTD value, which will result in the driver feeling additional oversteer. The same holds true at the rear of a car. Installing a stiffer rear sway bar will increase the rate of lateral load-transfer, placing more demand on the rear tires. This accelerates lateral traction loss at the front of the car, which will create a higher degree of understeer.

The tech guys at Hellwig tell us, “Many customers fall into the ‘bigger is better’ trap, and shop only for the largest sway bar they can find. Sometimes this works, but many times they are compromising their vehicle’s performance. If other modifications have been made – increased spring rate, lowered height, change in roll center, etc., the best sway bar may actually be smaller.”

In a nutshell, any vehicle is a combination of its parts, and it only cares how the sway bar interacts with the rest of its components. This is why Hellwig produces adjustable sway bars for many applications. The adjustable sway bar allows you to tune the vehicle to your driving style and suspension components. They also manufacture more than one diameter for popular applications to allow the customer to match the right sway bar to the vehicle.

Some time ago, we installed front and rear sway bars from Hellwig on a 1966 Chevelle, and if you want to check out the installation and before and after results, you can see the article here.