How To – Sway Bar

Discussing a sway bar and how it works is one of the most difficult parts of a suspension to explain. It is even harder to convince drivers why you want to use one when you are off-road. We are going to attempt it anyway and hopefully, even if you don’t agree with us, you will learn something new.

Sway Bar/Anti-Roll Bar 

The basics are generally described as follows: An anti-roll bar (anti-sway bar, sway bar, stabilizer bar) is a part of many automobile suspension systems that helps reduce the body roll of a vehicle during fast cornering or over road irregularities. It connects the opposite wheels together through short lever arms linked by a torsion spring.

As either wheel moves up or down it puts pressure on the roll bar. That pressure is transferred through the bar to the other side to try to move the opposing wheel the same direction. That force is not only passed through the sway bar but also through the chassis. The resistance to twisting is what prevents the chassis from wallowing from side to side. The pressure is not 1:1, the bar has some engineered twist to it dissipating some of the force. This allows you to tune how much body lean or movement you want the vehicle to have. Sway bars also help to balance the vehicle weight front to rear.

Many people disconnect the sway bar when they off road to get more suspension travel (articulation) when going over obstacles. It works and we aren’t here to argue that. We are here to present a compelling case that using a properly tuned set of sway bars off road may be a better option.

Off Road Disconnected
4WAAM-Jeep-Rubicon-Disconnect

The Jeep Wrangler Rubicon comes from the factory with a sway bar that is able to be disconnected electronically. It works great and it gives you more suspension movement off-road.

What is also does is put a lot of stress on the remaining sway bar in the rear. Watch a friend off road and you will see how little the rear end moves compared to the front.

Remove the rear sway bar at the same time and you get equal amounts of travel but a loss of stability. The suspension has nothing keeping it coordinated. If all you do is lowspeed rock crawling and don’t care if the body of your vehicle flops around like a wet fish this is the most articulation you can get out of a suspension.

Off Road Sway Bar 
Pictured is the Off Road Only SwayLOC. A dual rate sway bar.

A sway bar balances weight front to rear as well as side to side. It can control front end dive under hard braking or in our case body roll front to rear. This is where using that sway bar off road really comes into its own.

If you have ever driven off road and hit any off camber terrain without a sway bar you know how much the body of the vehicle tilts over towards the low side of the obstacle. Because there is no sway bar the body doesn’t try to stay parallel to the axles making these obstacles much harder to deal with. When you have both sway bars working together an obstacle gets shared between them. Instead of the front wheel traveling up 6 inches to climb a 6-inch rock, the front will go up 4 inches and the rear will drop 2 inches (These are approximate distances as the vehicle weight, sway bar specs, and several other factors determine actual travel). This is because the frame is transferring that movement from front to rear because the sway bar is transferring force from the axle movement to the frame.

That transfer side to side and crossways puts force into the ground which equals traction. You can flex like Stretch Armstrong but if you can’t put the power to the ground to move – you end up all twisted up and sitting still.

Traction is King

I think most of can agree that traction is the most important factor off-road. It’s why a beat up old farm truck with 0 suspension travel won Truck Night in America and why off-road racers hand groove tires to adjust grip when racing.

So the question is do you want an additional inch of articulation on an RTI ramp or do you want to wheel safer and stay more in control?

William Connor

As the Editor, William is responsible for all the good, the bad, the ugly and the indifferent that happens at 4WAAM. William brings a wide range of experience to this role. He also wields a freely shared opinion on just about everything., just ask him.