hollow vs. solid sway bar test

Are solid sway bars stronger than hollow sway bars?

It’s a frequently asked question from people preparing to make upgrades to their vehicle’s suspension because upgrading to a high performance sway bar is among the fastest, easiest, and most cost-effective ways to improve handling and control on a muscle car or classic vehicle.

As you’ll see in today’s video below, hollow (also called tubular) sway bars can actually outperform solid sway bars in a strength test while also providing a weight-savings advantage over the heavier solid bars.

Sway bars (also commonly called anti-sway bars, antiroll bars, or stabilizer bars) reduce body roll—the sudden transfer of weight to your outside wheels during hard turns—by tying together the left and right sides of a vehicle’s suspension. As vehicles a enter tight turn, sway bars absorb the cornering load, reducing body roll in the process, and helping tires stay glued to the road or track.

The two most important criteria in choosing a sway bar are the cross-section (diameter and wall thickness) and the distance between the end link and rotation point on the bar. These two factors affect the sway bar’s overall stiffness and ability to absorb cornering load.

Hollow sway bars like those offered by Hotchkis Sport Suspension are lighter than solid bars but have the same torsional rigidity due to increased diameter. This makes installation easier and improves front/rear weight balance.

(Interested in a total suspension upgrade? Check out this 5-Step Plan for Making Your Classic Muscle Car Handle Like a Late-Model.)

Wrestling with a hollow vs. solid sway bar decision? Here’s a science-based explanation from Hotchkis for the why the central core material in a solid sway bar won’t affect overall sway bar or suspension performance:

“Sway bars work off of torsional force (twisting motion). Therefore, the material in the center of a solid bar plays little role in the resistance of torsional force. With this in mind, we have eliminated some of the center material and also moved some to the outside of the tube, where it is most effective. In turn, this produces a sway bar that is lighter in weight and just as stiff, if not stiffer than solid. For example, a 1’3/8″ hollow bar is equivalent to a 1’1/4″ solid. But the 1’3/8″ hollow bar is 6 percent stiffer and 43 percent lighter than the 1’1/4″ solid.

Now, watch this short video to see hollow vs. solid sway bars being tested against each other.