While daydreaming, I came upon this question. Swaybars connect "opposite (left/right) wheels together through short lever arms linked by a torsion spring" as found on wikipedia.org. Essentially, whenever a car leans (like when going through a turn) the "lever arms" of the swaybar are forced in vertically opposite directions creating a torsional force on the portion of the sway bar that links both sides. Now, through my own experience (and I'm sure many others), springs soften and tend to sag with age and miles. Swaybars, although spending much less time than springs under force, are still essentially a spring that sees duty over the lifetime of a car. For example's sake, let's compare sway bars with 150k miles under the belt to an identical new old stock set. Do you think that the used set would have experienced enough duty over its lifetime to effectively lower the bar's resistance to torsional force and make them significantly inferior to the brand new bars? Discuss.

 

i would like to bellieve that swaybars do not flex or moveabout a lot during their duty cycle, unlike a spring that sits pretty much its whole life partially compressed under the weight of the car. I would think that swaybars would last pretty much indefinitly unless they are damaged by an outside force, ie deer, other car, big rock, ect.

 

The small ones probably fatigue some. Since they allow more roll, thus twist more. But for a 36mm swaybar that barely twists at all since its so freaking huge, will probably stay the same for the life of the car.