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As the name implies, sway bars or anti-roll bars prevent your car from rolling around corners like a boat on the high seas. If you like to take your car out on track days, you'll enjoy the benefits of a stiff sway bar.
All cars are equipped with anti-roll bars to keep your tires connected to the road and prevent passenger injuries.
The anti-roll bar itself is a simple piece of engineering. It's essentially a U-shaped cylindrical piece of metal that connects the left and right ends of the axle.
When you turn, the mass of your car shifts to the outside of the turn due to centrifugal force, causing the car to "roll". This is bad for car control and passenger comfort, and more roll means the car takes longer to respond to your commands.
By connecting the two ends, the sway bar forces both ends of the axle - in this case the wheels - to be raised or lowered to a similar height, preventing roll. The bars resist twisting or torsion through their torsional stiffness. The stiffer the crossbar, the less the car will turn and lean.
That's why some aftermarket sway bars are stiffer by using stronger materials or expanding their diameter for better handling and performance.
One benefit of such bars is that they can make the vehicle lean less without increasing suspension stiffness, which can affect ride quality.
Some bars can even be adjusted by the bar's mounting position to the end links or by a computer-controlled setup.
By removing the sway bar, the wheel articulation is much greater, which is why you often hear of frequent off-roaders "removing the sway bar" when rock climbing.
The anti-roll bar has another super important function - it acts as a second spring to increase the spring stiffness of the tire, but only in turns.
In racing, we need stiff springs to help us maintain maximum grip at the tire's contact patch for cornering. However, if we use springs that are too stiff, tire grip for braking and acceleration will be adversely affected. That's where sway bars come in - to increase the spring stiffness of the tire to help grip in turns, while decreasing the spring stiffness needed for braking and acceleration.
Together, springs and sway bars affect your grip in rolling mode - the most important phase of cornering. For road performance, all the same criteria apply, except we use softer springs to maintain an acceptable road ride.
The disadvantage of stiffer sway bars is that the crash forces on one wheel are transferred to the other, resulting in a very discordant motion. On rough roads, this can exacerbate the problem by causing the car to shake and rattle, thereby damaging everyone inside.
For us, sway bars are just a good thing when it comes to road performance and racing. We get all the stiffness we need to roll and don't exceed the reasonable stiffness for riding mode.
All in all, the anti-roll bar gives us the extra stiffness we need on the tire contact surface to maximize cornering grip. The sway bar provides us with a softer response in a one wheel crash. If you need to purchase one, please contact us promptly.
