Grip Guide Week #2: The Role of Sway Bars in Handling – A Deep Dive Into Anti-Roll Technology
Welcome back to Grip Guide! For this week’s edition, we’re diving into a critical suspension component that has a profound effect on how your Subaru handles, especially when cornering—the sway bar, also known as the anti-roll bar.
If you’ve ever felt body roll while taking a sharp turn or noticed your Subaru feeling unsteady during quick directional changes, this article is for you. Understanding sway bars and how they work can help you make informed decisions about upgrading or fine-tuning your suspension setup.
What is a Sway Bar?
A sway bar (or anti-roll bar) is a U-shaped metal bar that connects the left and right sides of the vehicle's suspension. Its main purpose is to reduce body roll—the tendency for the car to lean to one side during cornering. By connecting both sides of the suspension, the sway bar helps to balance the load more evenly between the inside and outside tires as the vehicle turns, improving stability and grip.
How Does It Work?
During a turn, the vehicle’s body naturally rolls toward the outside of the corner due to inertia. Without a sway bar, the suspension on the outside of the vehicle compresses while the inside suspension extends, resulting in significant body roll. When a sway bar is in place, it resists this movement by transferring some of the load from the outside wheel to the inside wheel, reducing the roll and improving overall balance.
This resistance helps:
- Minimize body roll during turns.
- Enhance cornering performance by keeping the tires more evenly loaded and in better contact with the road.
- Improve overall handling for a more stable and confident driving experience.
Sway Bars in Performance Applications
When it comes to performance driving, such as autocross or track events, sway bars can have a massive impact. Installing stiffer sway bars on your Subaru allows the suspension to resist roll more effectively, keeping the car flat during cornering. This can be particularly beneficial for high-speed cornering, where reducing roll means more predictable handling and faster cornering speeds.
Adjustable Sway Bars
Many performance sway bars are adjustable, allowing you to fine-tune how much resistance they provide. By changing the bar’s end-link position, you can make the bar stiffer or softer. A stiffer setting will offer more resistance to roll, which is ideal for track settings, while a softer setting can be better for daily driving or rougher roads where a little more body movement is acceptable.
The Balance Between Front and Rear Sway Bars
It’s important to understand that sway bars on both the front and rear axles work together to influence the car’s handling balance. Here’s how they work:
- Front Sway Bar: A stiffer front sway bar reduces front body roll and increases understeer (pushing the car toward the outside of the turn).
- Rear Sway Bar: A stiffer rear sway bar reduces rear body roll and increases oversteer (making the rear of the car swing around more readily).
Depending on your Subaru’s setup and driving preferences, you can adjust the front-to-rear sway bar stiffness to dial in the balance you prefer. For example:
- Understeer Reduction: If your Subaru has a tendency to understeer (common in AWD setups like the WRX and STI), upgrading or stiffening the rear sway bar relative to the front can help reduce this.
- Oversteer Reduction: If you find your car getting tail-happy, stiffening the front sway bar can help reduce oversteer and provide more stability.
How Subaru Models Benefit from Sway Bar Upgrades
Subaru’s iconic models, such as the WRX, STI, and even the Crosstrek, can all benefit from sway bar upgrades. Here’s how:
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WRX/STI: These models already handle well from the factory, but upgrading the sway bars, particularly for autocross or track driving, can significantly reduce body roll, providing sharper cornering and improved lap times. A common upgrade is a stiffer rear sway bar to reduce understeer.
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Crosstrek: If you’re using your Crosstrek for overlanding or off-road adventures, sway bars still play a role in balancing on road performance and off road articulation. You might want to keep a softer setting for uneven terrain, but adjustable sway bars give you the flexibility to tweak your setup for better stability on paved roads.
Choosing the Right Sway Bar Setup
When choosing a sway bar setup, it’s essential to consider:
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Driving Conditions: For street use, a mild sway bar upgrade (or adjusting to a softer setting) will balance comfort and performance. For track or autocross use, stiffer sway bars will help you extract more performance from your Subaru by improving grip and reducing body roll.
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Suspension Setup: Sway bars should complement your overall suspension setup, including coilovers and alignment settings. A stiffer sway bar might not be the best option if your springs and dampers are already stiff, as this could result in a harsher ride.
Conclusion
Sway bars are one of the most cost-effective ways to enhance your Subaru’s handling characteristics, whether you’re looking to sharpen your car’s track performance or make it more stable during spirited drives. By upgrading and adjusting your sway bars, you can fine-tune how your car handles in corners, making it more responsive and predictable.