I'm doing a paper for school, and I am having trouble getting a concrete explanation of how a sway bar works. Some say they work while cornering, where one side of the bar goes up, while pushing the other side down, keeping both tires on the ground. I also get sites saying that the sway bar exerts the same upward pressure on both sides. I am going nuts! If anyone has a link or quick advice, thanks.

 

stops body roll and twisting. basically for turning

 

I too wouldlike to know the answer to this question. To me the rear sway bar seems much too floppy to do much of anything to the suspension.

 

howstuffworks.com is a great place, dont know if they have sway bar write ups but something else like suspension could be in there

 

Just the basic principle without going into the details of the physics. Sway bars are used to counteract movements that cause a leaning tendency b/w the left and right (b/w the passengers side and drivers side) or what is generally known as body roll. Gravitational and Physics laws dictate that there is an equal and opposite reaction to every action. So when you accelerate your car (if it has enough power) it will throw you back in your seat, though the car moves forward. Same with cornering, when one side is in compression (the side that you are leaning on), the other side is in tension (the equal and opposite force). This creates roll, enough of it will cause you to eventually reach a threshold point at which one force overcomes the other and you are no longer balanced ie spinning out or flipping over. Sway bars counteract these forces by stabilizing the opposite forces to a more balanced distribution of force by making it tougher for the body to flex like such. The more performance oriented the sway bar is, the more rigid it generally is. This is done by using a larger diameter and strength of material which prevents body roll by eliminating alot of the flex that is otherwise present. Now, the more rigid the sway bar, the less roll, thus the more stiff around corners. The Force that is applied during cornering due to gravity etc and the turn has to go somewhere, so its a compromise of performance vs comfort.
As an ex: This is why when you have softer shocks and spring, you dont feel much inside the vehicle cabin; the shocks and springs absorb much of the impact of any bumps etc. But when you have a performance oriented shock spring set up, they do not absord the impact as much and therefore more of the impact force is transmitted through the vehicle and you feel the road more.

 

Your sway bars attatch the body of your car directly to your axle. They are designed to allow a certain degree of rotation but not twist. The shape of the bar allows the body to move up and down evenly on a verticle plane, but not UNevenly. If the car tries to sway to one side the bar will be pushed into a twist, which it resists.

A good example would be to take a coat hanger and bend it into a "U" shape with a flat bottom, then bend the very ends out 90 degrees, so it looks like a flared flower vase with a flat bottom. Place the top ends down on a table and hold it with BOTH hands at each bend on the bottom end. Hold it so it is at a 45 degree angle to the table. Now, when you raise or lower your end, you'll see the bar/coat hanger will rotate in your hands easily. However if you push down on only one end,itadds force to that one side, thus some of the pressure is transmitted directly to the axle, not throught the spring/shock. This what reduces body roll, the transmission of force to an unspung part of the vehicle, not all throught the suspension. I hope you can follow this, it's not easy for me to explain clear enough.

 

Try this http://www.houseofthud.com/cartech/swaybars.htm

 

"Sway bars, with their rigid structure,"


What "rigid structure"??? They are floppy. Just like the coat hanger described by drbobvs. I had my sway bar disconnected when I installed my Roush springs, and I was surprised how easy it was to torque and bend it. That's why I am not seeing it's usefulness.

 

Thats relative. Yes, stock are "floppy". I was referring to a performance oriented sway bar. That is exactly the intent of sway bars; to create a more rigid, less roll and flex structure.

 

The stock one is.....why do you think most replace them?

my BMR is pretty damn rigid.....weighs a good deal more than the stocker too....i noticed the new feel of both tire being firmly planted immediately once installed.