How Springs and Sway Bars Work and Why You Should Change Them

Photography: Whiteline Performance

  • Regardless of platform, springs and sway bars are arguably the most common suspension upgrades. 
  • Despite their popularity, there’s still a lot of misinformation about their inherent benefits or use case scenarios.
  • Suspension companies like Whiteline Performance try to create springs, sway bars, or combination packages to suit driver demand and style.

There is always low-hanging fruit when tuning a vehicle: a re-flashed ECU unlocks more power, a brake pad and fluid change ensures all-day stopping power on your first track day, or a tire upgrade brings more grip to a stock platform. On the suspension side, most enthusiasts look to spring and sway bar upgrades, not only as the place to start but also where some of the best upgrade ROI exists.

We agree. While they may look like rudimentary upgrades from afar, springs and sway bars offer the ability to address performance, appearance, and a range of other nuances all at once. Despite the benefits, one big problem still exists: how do you know when or what you really need to upgrade?

Indeed, part of the problem is that the articles surrounding this topic present themselves like engineering briefs. We spoke to Brett Hauschild, General Manager of Marketing & Strategy at Zeder Corporation, to get a real-world explanation of all things suspension.

Pit+Paddock: Fundamentally speaking, what are springs and sway bars?

Brett Hauschild: Springs support the weight of the vehicle and, in concert with the rest of the suspension, allow the upward and downward movement of the vehicle as it rolls over different terrain or road surfaces. Springs also dictate the ride height of the vehicle and impact several facets of performance.

Sway bars — or anti-roll bars — do exactly what their name implies. The bar acts as a spring that connects the two sides of the vehicle. Doing so, limits body roll and controls body motion during cornering events. Beyond that basic description, sway bars allow you to tune the handling balance of your vehicle.

Pit+Paddock: Sounds reasonable enough. Why would a typical enthusiast want to upgrade either of these?

Brett Hauschild: Spring upgrades can take a few different paths. Many are looking to simply change the ride height to achieve a more aggressive or purposeful stance. Others want a more responsive vehicle with a more taught and connected ride. Choosing your spring package correctly can allow you to optimize either, or reward you with both.

On the sway bar front, there are a few reasons to upgrade depending on what you drive. If you’ve added a roof rack and rooftop tent to your 4Runner or Wrangler you’ve just added a bunch of weight to the topmost part of your truck. This will exaggerate body roll as that greater mass makes itself known in corners. Moving to thicker diameter sway bars will help keep that movement in check. These aftermarket sway bar upgrades should reset overall body control back to stock, or in many cases vastly improve it, making the vehicle more stable and predictable.

For performance vehicles (especially newer ones), you’ll find that most are set up to exhibit understeer as you approach the limits of grip. As a result, the car will push wide of the path you’re directing it to follow. While understeer may be objectively “better” for novice drivers in emergency situations, most enthusiasts will prefer a more neutral handling balance where the limits of grip are reached by both ends of the car simultaneously. In this case, the car’s balance can be adjusted from behind the wheel with steering and throttle inputs. For more confident drivers, a more oversteer-biased setup can also be achieved with the right sway bar setup where the rear end of the car is more willing to rotate around corners.

Pit+Paddock: So both upgrades are definitely dependent on driver preference. How do I choose the best spring option for me?

Brett Hauschild: Our rule of thumb is to identify how you want the car to improve. Once you know that, you can identify what can be upgraded to achieve that aim.

If the answer is that you like the way the car rides and handles, but your new wheels really need to be complimented by the perfect drop, there is no shortage of springs to choose from. What you’ll want to consider is whether you’re looking for a matched set of springs and dampers or if you want to keep the OEM shocks/struts. Companies like Tein and H&R not only offer different ride height options but also spring ranges well suited to the OEM dampers — especially electronically adjustable ones — to maintain excellent ride quality alongside the improved look.

If you’re passing on the show car scene to blitz your favorite backroad or move up the time sheets at the local Autocross, you’ll want a true sport spring. Most often these will still lower the car mildly, but carry higher spring rates for more response. Crucially, these springs still allow ample shock travel to avoid bottoming out and compromising performance.

Choosing the right spring will involve knowing how the manufacturer designed the springs to work best. Fortunately, manufacturers like Whiteline Performance develop their springs to overlap the performance window between the OE dampers and performance shocks/struts like those offered by Bilstein and Koni.

Pit+Paddock: Got it! What about sway bars?

Brett Hauschild: If changing the appearance of your car is the game, sway bars will stay on the sidelines. If changing the balance or attitude of the car is at the top of the list, you may want to start with the bars. As we talked about before, if the car is more willing to rotate, it immediately makes for a more engaging and playful driving experience. Choose any sought-after enthusiast car from the last several decades and you’ll find a common thread tied to its responsiveness, balance, and how it responds to the driver.

Pit+Paddock: We’ve seen drivers upgrade only front, only rear, or both sway bars. How do you decide?

Brett Hauschild: On front-wheel drive and all-wheel drive applications, a larger rear bar wakes up the rear end of the car and encourages that rotation we just talked about. The opposite is true for rear-wheel drive cars that upgrade front bars. Upgrading both isn’t always necessary, but again it largely depends on how you want the car to improve.

Many suspension specialists will offer multiple bar sizes. This can make your initial decision tough, but should you need to size up or down, most sway bar installations are quick and easy. Even better, Whiteline, H&R, and Cusco all offer a range of adjustable sway bar options, too. By installing an adjustable (multi-position) bar, you can scale the impact of the bar to suit your driving style. Best of all, this is an adjustment that takes only a few minutes with common hand tools.

Pit+Paddock: OK, adjustable sway bars definitely add another layer of complexity! How do you decide where to set your bar(s)?

Brett Hauschild: There is really no wrong answer here. Every driver may like a slightly different default balance, but we implore you: get out on your favorite roads and try several settings or take a small tool kit and some ramps to your next track day. In minutes, you can dial the car’s balance to your liking.

Pit+Paddock: That’s great advice. Now what happens if you want to upgrade both springs and sway bars?

Brett Hauschild: Now we’re talking. Brands like Whiteline Performance and H&R offer spring and bar combos where they’ve paired their preferred bar and spring kits together for you. While any mix of parts can be installed together, there is one big advantage to these manufacturer-bundled kits: they are designed with harmonious handling and ride quality in mind. These kits are often compiled with feedback from their respective development teams and take out all the guesswork. Essentially, you can get all the above benefits from a single SKU.

In the end, both upgrades serve a specific purpose. In most cases, spring and sway bar upgrades are relatively straightforward to install, and similarly, can be removed just as easily when it comes time to turn in a leased car or make more extensive upgrades.

We’d like to thank Brett Hauschild, General Manager of Marketing & Strategy at Zeder Corporation for taking the time to chat with us. For more information on springs, sway bars, or other suspension upgrades, visit the company’s website.