Tighten Up The Handling On Your 2015 Mustang With Hellwig Sway Bars

hellwig15stangleadartThe introduction of the sixth generation Mustang for 2015 brought with it a bevy of changes to the iconic pony car. Along with a clean-sheet approach to its appearance, one of the key engineering focuses with the S550 Mustang was to improve ride and handling.


Right out of the box, we knew right away that Hellwig was going to improve the handling of this new Mustang.

To that end the new car is both wider and lower, and for the first time in its fifty year run, every new Mustang now features fully independent rear suspension – an upgrade that’s been a long time coming, and one that was an ongoing item of contention among the Blue Oval faithful for many years.

Compared to its predecessor, the new car feels substantially more planted in the corners than the solid-axle Mustangs did, but as any gearhead worth his or her salt already knows, there’s always room for improvement.

Even on performance cars like the Mustang, the factory suspension tuning for the majority of new vehicles is designed to keep drivers out of trouble if things start to get unruly, and the easiest way to do that is to dial in the car for understeer at the limit. That’s perfectly fine for the majority of motorists, but for enthusiasts, understeer is more or less the opposite of fun.

Hellwig Performance Sway Bars

Part number 56715 – Front, 56815 – Rear

  • Direct replacement
  • Three adjustments, front and rear
  • 1-3/8-inch front, 1-inch rear diameters
  • Reuse factory end links
  • Polyurethane bushings
  • Limited lifetime warranty
Fortunately, altering this behavior toward a more neutral handling balance can be easily accomplished by swapping out the stock sway bars for something a little more performance oriented, and our friends at Hellwig Products, a company that’s been building suspension components in-house in the USA since 1946, have stepped up to offer just such an upgrade.

“The roll stiffness of a vehicle determines not only the amount of body roll it exhibits but also understeer/neutral steer/oversteer,” says Ben Knaus at Hellwig. “Roll stiffness is determined by the entire suspension but a sway bar is there specifically to increase this.”

“In our sway bar design we increase the total roll stiffness as well as changing the front to rear ratio to bring the vehicle closer to a neutral steer setup. This allows the driver to corner faster and more confidently and makes the car more fun to drive,” he said. These adjustments can help tune the oversteer and understeer characteristics of your car.

The adjustments on the sway bars will provide varying levels of stiffness based on the setting used. These rates, noted below, are based on the installed strength of the bars, not the static rates. These rates include a 20% loss to account for bushing compliance, so they might appear to be different than other bars on the market that are listed at their static rate.

Front Bar Rear Bar
Part #56715 – 1-3/8-inch tube Part #56815 – 1-inch tube
Firm –  489 lb/in Firm –  273 lb/in
Middle –  432 lb/in Middle –  226 lb/in
Soft –  391 lb/in Soft –  174 lb/in

We’re going install a set of Hellwig’s sways on a 2015 EcoBoost Mustang for an owner who’s looking to button down the handling a bit and make his car a little more receptive to the drifting he’s planning to do with it. While it’s a relatively painless procedure, there’s definitely some items of note along the way.

Front Sway Bar Installation


We discovered that getting to the front sway bar bracket bolts was easier from the top rather than from underneath the car. On the driver’s side we removed the airbox for access.

The good news here is that, on the whole, swapping out the front sway bar is an easier procedure than it was on previous Mustangs. These bars use the factory end links and do not require any drilling or cutting.

Once the car was up in the air, we cranked the wheel to the right to provide clearance through the wheel well to get the old sway bar out. We removed the subframe cover panel so the stock piece had enough room to be liberated from the car.

On this EcoBoost model we found that removing the airbox made accessing the bracket on the driver’s side an easier task. For V8 models, check for access and anything that is in the way can likely be easily removed for removal and installation.

Removing the covers under the front of the car allowed access to the right side clamp.

Access from underneath on the passenger side was a breeze though – just make sure you have a very long socket extension to access the sway bar bracket bolts as well as the bolts attaching the sway bar to the subframe.

The airbox on the 4 cylinder EcoBoost made it difficult to get to the clamps, removing it was quick and easy, and gave us plenty of access to the bolts.

Now with everything unbolted the stock sway bar comes out by sliding it out through that gap we created on the driver’s side wheel well by cranking the wheel to the right, and the new bar goes in by reversing the process. Once the new bar is in place, we lubricated and installed the bushings using the factory hardware, torquing the bolts down to 35 ft-lb.


Unlike earlier Mustangs, the front sway bar on the 2015 Model doesn't require a lot of effort to remove it - even the front wheel stayed on the car during the swap to Hellwig sway bars.


Not only are the new bars noticeably thicker than stock, Hellwig’s sway bars offer the ability to adjust how aggressively they affect the car’s handling. Hellwig recommends using the center mounting point until you’ve had a chance to get used to the new bars and then adjust to taste, if needed. The outer hole is the mildest setting. End link nuts should be torqued to 35 lb-ft.

One particularly cool feature of Hellwig bars is that they use a hammertone powder coating on the bars because the small pockets in the finish help to trap the grease instead of squeezing it out when the bushing is clamped down. This helps ensure that the grease stays where it should, reducing the need to re-lubricate the bushings down the line.

This allows the customer to switch the front to rear bias depending on what track they’re on, who’s driving the car, or even change it between settings for track and daily driving. -Ben Knaus

Another cool feature is that these sway bars also have three different end link mounting points at both the front and back. This feature really allows you to dial in your handling for track or street performance.

Knaus explains the benefits as such, “In the case of the Mustang, both the front and rear bars have multiple attachment points for the end links. This allows the driver to tune their sway bar to fit exactly what they’re doing with the vehicle and their driving style. Basically, the different holes change the length of the effective arm of the sway bar, changing its rate. This allows the customer to switch the front to rear bias depending on what track they’re on, who’s driving the car, or even change it between settings for track and daily driving.”

Knaus recommends starting at the hole the furthest out before you start adjusting the settings. These bars are already stiffer than the factory bars and they will change the handling on the car. Once the new bar was hooked up to the the end links we centered the sway bar again, attached the collar clamps, and made sure everything was copacetic in terms of clearance with other systems under the car. With it all buttoned up we moved on to the rear sway bar installation.

Despite being a bit thicker, the front Hellwig bar still slides into place with a little bit of finesse.

Rear Sway Bar Installation


The first step on the rear is to remove the rear link. Clearance is tight, but with some patience it can be removed.

Although Hellwig’s instructions recommend dropping down the exhaust to get the new bar in, we were able to do it without going through that process. However, space is pretty tight back here, especially at the end links, so your application may vary.

We started by disconnecting the brake hose and its bracket, noting the orientation of the brake hose tabs before disconnecting the stock bar from the end links, as we’ll have need to flatten out the tab on one of them for clearance with the new sway bar.

The end links have ball-joint style ends and call for the use of an Allen wrench and box end to remove. Keep in mind that the Allen head socket in the bolt can easily be stripped, so make sure to use the Allen wrench to hold it in place, not to turn the bolt.

The tab on this brake hose bracket must be flattened for clearance to install the new rear sway bar. We recommend using a vice grip if you have one available, but a hammer will get the job done too.

With that done, we removed the bolts attaching the factory sway bar to subframe and removed it from the car. After lubricating the bushings, the new bar gets attached to the subframe using supplied u-plates and factory hardware, torqued to 25 ft-lb.

Like the front bar, the Hellwig rear sway bar has three different mounting points to adjust the handling at the end links. And also like the front bar, Hellwig recommends using the center mounting point until you've had a chance to get acclimated to the changes in the car's handling. The rear end link nuts get torqued down to 40 ft-lb.

Reattaching to the end links is just a reversal of the removal process, making sure to attach the brake hose bracket in the correct orientation. Once that’s out of the way, the bar gets centered and the collar clamps go back on. With everything back in one piece again, it’s time to head out for a test drive.

Hellwig also supplies the grease for the bushings and the stop collars that are mounted to the bars to help keep them centered on the Mustang's suspension.


Out On The Road

Even utilizing the middle end link setting, the results are instantly noticeable out on the road. Body roll has been curtailed substantially and there’s more of an overall sense that the car is rotating on a pin in the center of the vehicle rather than it begin a tug-of-war between front end grip and on-throttle rotation from the rear.


Increased body control and flatter cornering are immediately noticeable with the new bars on the car, and if this owner should decide he wants to go more (or less) aggressive, the handling can be dialed in by just switching mounting points at the end links.

The car owner was looking for better handling and less body roll so that he could try a little drifting with his car. When we asked how it handled with the new Hellwig Sway bars, he mentioned that it does allow him to drive a little faster in the turns because the car has leveled out substantially during hard cornering.

And contrary to what some people believe, swapping out the sway bars has minimal impact on the Mustang’s ride quality. For S-550 Mustang owners looking to upgrade their handling without affecting the suspension geometry and compliance, this is a great place to start.

Whether it’s the new 2015 Mustang or just about any other classic or modern musclecar, you can find a set of sway bars for hundreds of applications through the Hellwig Products website. If you’re not sure about your application, they’re always available to help you out and get your body roll under control.

Article Sources

About the author

Bradley Iger

Lover of noisy cars, noisy music, and noisy bulldogs, Brad can often be found flogging something expensive along the twisting tarmac of the Angeles Forest.
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