The "Understeer" Fix: How to Tune Your S550's Handling with Adjustable Sway Bars
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You take your 2015–2023 Mustang GT to an autocross event, a track day, or a twisty canyon road.
You enter a corner fast. You turn the steering wheel sharply.
The tires scream, the heavy body leans completely over, and the front of the car just wants to keep going straight towards the outside of the turn.
This is known as "Understeer" (or plowing), and Ford intentionally engineers it into the Mustang from the factory because it is the safest, most predictable way for an average driver to lose traction.
But you aren't an average driver, and you want performance. You want the car to rotate sharply and point exactly where you steer it.
You don't necessarily need an aggressive set of coilovers to fix this. You need premium Adjustable Sway Bars.
By stiffening the rear sway bar relative to the front, you fundamentally alter the mechanical balance of the car, neutralizing that factory understeer and locking the chassis down flat.
In this guide, we explain the "Leverage Math" behind the adjustment holes on Steeda and Eibach bars, and why you absolutely must upgrade to Adjustable End Links if you’ve already lowered your suspension.
Compare Premium Sway Bar Upgrades
Street Compliance or Track Precision?
|
Brand / Series |
Construction Type |
Adjustability |
Best For |
|
Steeda Competition |
Hollow / Tubular. |
3-Way / 4-Way. |
Track/Autocross. The gold standard for S550 handling with maximum tuning range. |
|
Eibach Anti-Roll Kit |
Hollow / Tubular. |
3-Way (Front & Rear). |
Street/Canyon. Perfectly paired with Eibach lowering springs for a balanced ride. |
|
Ford Performance |
Tubular. |
Adjustable. |
OEM+ Track. Factory-level durability developed on the track. |
|
Whiteline |
Solid Spring Steel. |
Adjustable. |
Heavy Duty. Precision lockdown and incredible durability under high lateral G-forces. |
Frequently Asked Questions (Sway Bars)
Do I really need adjustable end links?
If your Mustang is lowered, absolutely.
When you lower an S550 Mustang, the static distance between the sway bar and the control arm changes. If you reuse the fixed-length factory end links, it puts "preload" (constant tension) on the sway bar, meaning the bar is twisted even when the car is sitting completely still. This makes your handling erratic and unpredictable. Premium Adjustable End Links (from brands like Whiteline) allow you to change the length of the rod to zero out that tension, ensuring the bar only activates when you actually turn the wheel.
Will stiffer sway bars make my daily commute uncomfortable?
In a straight line, no. Over uneven bumps, slightly.
Unlike drastically stiff lowering springs that make you feel every pebble in the road, sway bars primarily activate when the car leans (corners). When you are driving straight down the highway and hit a dip with both front wheels simultaneously, the sway bar rotates freely and does very little. However, if you hit a pothole with one wheel, the stiffer bar will transfer some of that impact to the other side (known as "head toss"). It is the best way to get flat cornering without a back-breaking daily ride.
Which setting should I use on my adjustable bars?
Start right in the middle.
- Rear Bar: Installing a stiffer rear bar reduces factory understeer (plowing) and helps the rear end rotate. If the car feels too "tail happy" (oversteer) on corner exit, simply move the end link to the softer hole.
- Front Bar: Stiffening the front helps turn-in response and keeps the car flat, but can increase understeer if set too stiff.
Most street-driven S550s perform best on the Middle Front / Middle Rear settings.
Stay flat.
Tune your handling, dial out understeer, and eliminate body roll. Shop our verified collection of premium 2015–2023 Ford Mustang Sway Bars & End Links.