Diameter of swaybar VS veichle weight?

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Caprimaniac
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Diameter of swaybar VS veichle weight?

Post by Caprimaniac » Wed Jan 11, 2017 6:17 am

Heeeeelo.

Looking through some easily obtainable swaybar kits, and found the Currie "Antirock" swaybar kits that might suit my needs- you can order it With bent arms and in different lengths,

http://www.currieenterprises.com/CE-9901-20B

Thh thing is; the diameter of the swaybar only comes in 0.8" diameter. For a front roadrace Application, would it suit my 2200 lbs roadrace car? CG is low....

(In afterthought, I MIGHT have worked some formulaes on this earlier, but I do not recall..... An i have never used this type of tube- mounted swaybars; they might be more effective than the 70's Capri's which I am used to.....And they twist alot....)

Other Sources for GOOD ARB setups might also be interesting...
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Re: Diameter of swaybar VS veichle weight?

Post by chimpvalet » Wed Jan 11, 2017 2:26 pm

A low cost method you might use in order to explore whether your car performs better with more front bar is to have a temporary add-on bar fabricated. Take a length of steel bar 70 - 90% of the current bar diameter, add 2 bends then clamp both together in 4 places ( near both chassis pivots and at each end ) with sturdy blocks. Assuming adequately firm chassis mounts, you can track test this as a temporary set-up before laying out cash for a bigger bar properly shaped to fit the chassis. In my experience the effective roll resistance of the dual bar set is very close to the sum of the 2 bars' resistance. Find a combination that you like then do the calculations for torsion rate versus lever arm of each bar in the set, add them up then do the calculation for diameter of single bar that would be equivalent to the combined pair.
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Re: Diameter of swaybar VS veichle weight?

Post by chimpvalet » Wed Jan 11, 2017 2:30 pm

An even lower cost source for the add-on bar might be to source one close to the correct shape from a salvage ( scrap ) yard. You would still require the attachment blocks but would possibly avoid cost or effort of bending and cutting a piece of straight stock.

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Re: Diameter of swaybar VS veichle weight?

Post by turbo2256b » Wed Jan 11, 2017 4:22 pm

Do a search on " 3 piece sway bars". Several companies offer the splined end style in several configurations

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Re: Diameter of swaybar VS veichle weight?

Post by PackardV8 » Wed Jan 11, 2017 4:58 pm

The diameter is only one factor in the equation. The length of the lateral links determines their leverage against the bar's resistance, then where it's attached on the lower A-arm and the travel thereof determines the degrees of twist.

FWIW, make the effort to get a tubular or gun drilled bar splined for adjustable lateral links.
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Re: Diameter of swaybar VS veichle weight?

Post by MadBill » Wed Jan 11, 2017 7:14 pm

But by far the most important dimension is the diameter, since the stiffness varies as its fourth power. E.g., all else equal, the straight torsion segment of a 1.25" bar is ~ 250% stiffer than a 1.00" one.
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Re: Diameter of swaybar VS veichle weight?

Post by MadBill » Wed Jan 11, 2017 8:58 pm

To answer the question about suitability, you first need to ask yourself what you're looking to accomplish? Less body roll to improve dynamic camber angles and available suspension travel, reducing under or over-steer, etc.?
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Re: Diameter of swaybar VS veichle weight?

Post by Brian P » Thu Jan 12, 2017 6:41 pm

There are far too many variables involved for any "simple" calculation of antiroll bar diameter to have any relevance.

Plenty of vehicles have been built with no antiroll bars at all.

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Re: Diameter of swaybar VS veichle weight?

Post by pdq67 » Fri Jan 13, 2017 6:03 am

What does ADDCO have to offer for your vehicle?

Might be better to just buy one say, a next dia. bigger and try it?

I have ADDCO front and rear S/B's on my 1st Gen. now. Nothing fancy, just good value by me. I got them from JCW years and years ago.

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Re: Diameter of swaybar VS veichle weight?

Post by turbo2256b » Fri Jan 13, 2017 10:46 am

The trend in handling these days is the 3 piece straight bar. It allows for lesser spring rates but the higher stiffness of the straight 3 piece advantage less body roll along with the advantage of lowering the vehicle further.
The straight bar also has the advantage of more accurate twist ratings.

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Re: Diameter of swaybar VS veichle weight?

Post by j-c-c » Fri Jan 13, 2017 5:52 pm

Brian P wrote:There are far too many variables involved for any "simple" calculation of antiroll bar diameter to have any relevance.

Plenty of vehicles have been built with no antiroll bars at all.
I agree, like asking what size underwear should one buy?

The best advice I can give, whatever you buy first, can be bettered.

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Re: Diameter of swaybar VS veichle weight?

Post by chimpvalet » Sat Jan 14, 2017 3:01 pm

If the car is a Capri of the sort sold in NA, Europe and the UK back in the '70's it will use the A-R bar as a locating link, triangulating with the lower TCA. If that's the case it may not be possible to switch over to a 3-piece bar without modifying the chassis for an additional trailing link ( or is that leading link?).

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