Ever wonder how sway bars function? Visit
- posted
18 years ago
Ever wonder how sway bars function? Visit
On 11 Sep 2005 08:23:09 -0700, snipped-for-privacy@charter.net wrote:
Ever wonder how SPAMMING works?
For those who ARE interested (in what he has to say about sway bars) but don't WANT to visit his COMMERCIAL site:
How sway bars work, and why people use them. Here's how a sway bar works.
Normally, without a sway bar when the car corners the weight of the chassis shifts toward the outside of the turn compressing the springs on that side. The springs on the inside generally extend a little, or do nothing. Relatively to the chassis itself, it appears that the outside suspension compresses and the inside doesn't.
A sway bar couples the suspensions on each side to each other, *AND* relative to the chassis. If you could put the car up on a lift and actually compress the suspension on one side by hand, then a sway bar makes the compression of one side also try to compress the suspension on the other. Ok.. it's still not really obvious why that's useful so I'll say the same thing a different way.
A sway bar effectively increases the spring rate on whichever side is compressed the MOST. If the sway bar were absolutely solid with no twist so there's a 100% coupling between each side then an attempt to compress one spring actually becomes an attempt to compress both springs. It doubles the spring rate. If the bar has some twist, then it may only increase the spring rate by say 50% on whichever side is compressed the most.
So you're driving down the road and you go over a bump that goes across the entire lane. The sway bar does nothing. Both sides compress normally. You go around a corner and the chassis starts to lean and compress the outside suspension and now it's as though you have a bigger spring out there, so the car remains more level. That's the good part. Here's the bad part. You hit a bump with only one side, and it behaves the same way, as though you have a stiffer spring, so you feel uneven bumps more. You feel it crossing anything diagonally as well, such as coming into or out of a parking lot or driveway curb.
That's all the simple "How does a sway bar work?" part. The real tricky one is.. "What does a sway bar do?"
Here's where it gets really tricky. If decreasing the size of the rear bar doesn't help enough the next thing you do is increase the size of the front bar. When the outside front compresses in a corner, it causes the inside front to compress and may actually lift that tire completely off the ground. The car is now sitting on 3 tires and guess where the weight that was on the inside front goes? Outside front? Some of it. The rest goes to the inside rear where we need more grip. The total weight of the car hasn't changed. It's just been redistributed, and a sway bar at one end, actually transfered weight to the other end of the car.
Not.
Wrong. The action of a sway bar has nothing to do with the spring rates on the suspension and everything to do with the torsional spring rate of the sway bar. A thicker sway bar will resist sway much better than a thinner one and this has nothing to do with the spring rates of the suspension.
Matt
Jesus H. Christ!...I'm sorry that I even thought of asking!...
Thanks. Interesting read. jor
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