Suspension/Sway bar Question

[Guest Anonymous]

My understanding of sway bars is (correct me if I'm wrong) is that they are basically a spring. In a straight line they just sit there doing very little. In a turn, lateral forces bring the bar into play effectively raising spring rates. On a street car reduced spring rates coupled with sway bars will give a decent ride with less body roll in the turns.

 

Question is, on a track car, could the suspension be tuned with just stiffer springs and leave off the weight of the sway bars?

 

Mark

[JMortensen]

My understanding of swaybars is a little different. Rather than twist on the bar making the spring rate on the outside stiffer, I think they push the inside suspension down (or keep the suspension from extending on the inside) keeping the body from rolling.

 

Yes, lots of road racers run super stiff springs and the stock front bar and no rear. Another idea to consider is a tubular bar since it wouldn't add so much weight and could be run with a softer setup, which is more forgiving. A lot of racing parts places have generic tubular bars which could be adapted.

 

There are LOTS of other places to cut weight before the sway bar weights come into play IMO.

 

Jon

[Guest Anonymous]

Thanks for the reply, I'm considering the tubular bars from speedway but just trying to get all my ducks in a row before I start spending. mark

[Phantom]

Mark - I think what you were thinking of is a "torsion bar" like Chrysler used on the front suspension of some of it's cars back in the 60's & 70's. It actually replaced the spring and allowed the suspension to move by actually twisting the steel bar.

[JMortensen]

A sway bar IS a torsion bar. It's just connected to the control arm on both ends instead of the control arm on one end and the frame on the other.

 

Jon

[johnc]

Quiz:

 

Does an anti-roll bar with different arm lengths induce asymetry into the suspension? ie: if you adjust only 1 arm on an adjustable anti-roll bar, does it make that end of the car handle differently in left and right turns?

[JMortensen]

No. The center part of the bar does the twisting, and the length of the arms relative to each other doesn't matter because the spring acts on both arms all the time. I think....

 

EDIT--No, I am sure now. I remember adjusting sway bars and the next hole was too far, so we moved one side only.

 

Jon

[BillZ260]

Yes.

 

I really have no clue, but if JM's description is correct, sounds good, then it should have an affect on the handling if the ends are different lengths. The "levers" would be of un-equal lenth and one end would apply more pressure then the other in equal rate turns of opposite direction. Right?

[Guest Anonymous]

I would say un equal lenght arms on the bar would make the car handle different left to right.

[gramercyjam]

What I have read is that it doesn't. I think I even used to believe this. But right now it seems completely counter-intuitive.

[johnc]

An anti-roll bar is a torsion spring, just like a torsion bar, and a coil spring (which is really a wound up torsion bar). The anti-roll bar does not "see" separate arms, it just sees one arm that's the combined lengths of both arms. That's why the blade adjustable anti-roll bars run on many high end race cars only have one adjusting blade.

[CruxGNZ]

I love it when John pipes in, you always learn something . I would have said "Yes" to his quiz.

 

!M!