Solid Sway bars?
05-21-2006, 05:19 PM
#11
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From here:
http://en.wikibooks.org/wiki/Solid_M...orsion_Formula
The formula I'm using is:
J = πc4/2
For a hollow tube you would subtract the moment of the hole from a solid body, I'm not sure where your formulas would fit in.
The mass at the outside of the profile is the most important, the mass in the center matters little. Yes a solid bar is slightly stronger, but in the whole it is very little. Making a solid bar for a sway bar is wastful and heavy, a larger diameter bar is better.
Do you have the dimensions of the wall thickness of an anti-sway bar?
-T
http://en.wikibooks.org/wiki/Solid_M...orsion_Formula
The formula I'm using is:
J = πc4/2
For a hollow tube you would subtract the moment of the hole from a solid body, I'm not sure where your formulas would fit in.
The mass at the outside of the profile is the most important, the mass in the center matters little. Yes a solid bar is slightly stronger, but in the whole it is very little. Making a solid bar for a sway bar is wastful and heavy, a larger diameter bar is better.
Do you have the dimensions of the wall thickness of an anti-sway bar?
-T
05-21-2006, 06:54 PM
#12
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The bar can be assumed a thin walled hollow section.
http://www.physics.uoguelph.ca/tutor...e.inertia.html
My estimate of wall thickness is about 0.5 - .75 mm
See the difference in the formula for thin walled hollow vs solid in the formulas.
That is a factor of 2.0
Of course you can increase the stiffness similarly by simply increasing the diameter of the thin walled hollow rod and it wouldn't take much because the strength increases by the 4 th power of the diameter change.
Now back to the basic question of where can I find out the part number of a solid 32 mm bar and its bushings.
Yes I want solid and larger diameter.
The bars in both of my other Pontiacs are 32 mm solid and it'* a world of difference.
http://www.physics.uoguelph.ca/tutor...e.inertia.html
My estimate of wall thickness is about 0.5 - .75 mm
See the difference in the formula for thin walled hollow vs solid in the formulas.
That is a factor of 2.0
Of course you can increase the stiffness similarly by simply increasing the diameter of the thin walled hollow rod and it wouldn't take much because the strength increases by the 4 th power of the diameter change.
Now back to the basic question of where can I find out the part number of a solid 32 mm bar and its bushings.
Yes I want solid and larger diameter.
The bars in both of my other Pontiacs are 32 mm solid and it'* a world of difference.
05-21-2006, 08:21 PM
#13
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I don't know if GM does the same on the H-bodies, but on the W-bodies, the sways are hollow. I upgraded to the GMPP kit and got solid and thicker bars.
Too bad they don't make em for the H chassis.
Too bad they don't make em for the H chassis.
05-21-2006, 08:58 PM
#14
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A solid swaybar for the 2k+ crowd with the same outer diameter of the hollow bar would increase handling without having to increase the diameter of the bar. Period.
And a solid bar of the same outside diameter as a hollow bar is more twist and bend resistant than a hollow bar REGARDLESS of wall thickness. Period.
And a solid bar of the same outside diameter as a hollow bar is more twist and bend resistant than a hollow bar REGARDLESS of wall thickness. Period.
05-22-2006, 05:25 AM
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Yes, but by very little, period. I highly doubt the wall thickness is .5-.75mm, in fact I would put money that it is not. The ones I have seen were over 1/4".
-T
-T
05-22-2006, 09:30 AM
#16
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Comparing a 1" thick solid bar to a 1" tube with .25" wall thickness (probably thicker than most applications), the solid bar is almost 7% stiffer.
Most 1" swaybars have thinner walls than .25". The primary reason cars today have hollow bars is for weight savings.
Most 1" swaybars have thinner walls than .25". The primary reason cars today have hollow bars is for weight savings.
Note, however, that the stiffness of the bar is proportional to the diameter of the bar raised to the 4th power, so a small increase in diameter yields a large increase in stiffness. On the other hand, the nominal gains are less than that, because solid bars are, other things being equal, stiffer than hollow bars.
The stiffness of any torsion bar (and that'* what an anti-roll bar is) can be approximated using this equation:
K = 1,178,000 x (D4 / LA2)
Where K = bar rate in lbs/inch D4 = diameter of the bar, raised to the 4th power, measured in inches L = center length of the bar, measured in inches A2 = lever arm length, squared, measured in inches and 1,178,000 is the rigidity modulus constant
When you are working with solid bars, D= the outside diameter (O.D.) of the bar. When you are working with hollow bars, D = the wall thickness of the tubing, NOT the O.D. of the bar.
So, if company "A" offers a 28mm. hollow bar for your car, and NEUSPEED offers a 28mm solid bar for your car, the solid bar will have the higher rate if the lever arm and center lengths are held constant. Do the math before purchasing a hollow bar. It may be lighter, but it'* not as stiff as a solid bar if the O.D.'* are the same.
The stiffness of an anti-roll bar may also be calculated based on the torque force required to deflect the lever arm by 1 degree. The mathematical formula is different, and the unit of measure is Inch-pounds per Degree.
K = 1,178,000 x (D4 / LA2)
Where K = bar rate in lbs/inch D4 = diameter of the bar, raised to the 4th power, measured in inches L = center length of the bar, measured in inches A2 = lever arm length, squared, measured in inches and 1,178,000 is the rigidity modulus constant
When you are working with solid bars, D= the outside diameter (O.D.) of the bar. When you are working with hollow bars, D = the wall thickness of the tubing, NOT the O.D. of the bar.
So, if company "A" offers a 28mm. hollow bar for your car, and NEUSPEED offers a 28mm solid bar for your car, the solid bar will have the higher rate if the lever arm and center lengths are held constant. Do the math before purchasing a hollow bar. It may be lighter, but it'* not as stiff as a solid bar if the O.D.'* are the same.
The stiffness of an anti-roll bar may also be calculated based on the torque force required to deflect the lever arm by 1 degree. The mathematical formula is different, and the unit of measure is Inch-pounds per Degree.
05-22-2006, 01:21 PM
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Yes, but by very little, period. I highly doubt the wall thickness is .5-.75mm, in fact I would put money that it is not. The ones I have seen were over 1/4".
1/4" thick wall thickness is
It is a thin walled tube made from drawn metal not rolled and welded plate
Here'* another analogy. Combine this thin walled 30 mm tubular bar with a solid 28 mm bar that would fit inside the this tube. Now tell me that the combined stiffness of both bars would not be greater than just the tube.
Now come on Keith, be a man and admit you're wrong.
No matter. I will replace mine with a solid bar. I'll cut my old one just to prove how thin walled it is but I'm a pretty good judge of metal thickness by simply ringing it with a hammer. It'* likely 1 mm or 1/32" wall thickness.
I have contacted Saner and expect a quote soon.
Guaranteed that it will handle flatter and not rock like a boat the way it does now.
05-22-2006, 09:36 PM
#18
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Paul is absolutely correct from an Engineering standpoint and a logic standpoint.
Regardless of wall thickness, a solid bar will resist flex more than a hollow bar of the same OD.
The wall thickness determines how much that percentage of change is.
Regardless of wall thickness, a solid bar will resist flex more than a hollow bar of the same OD.
The wall thickness determines how much that percentage of change is.
05-23-2006, 05:46 AM
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Guys my math is correct. Look it up, I found the same formula on 5 different website refering directly to sway bar diameters.
No one ever said a hollow bar is stronger then a solid bar of the same diameter.
Do you have proof that it is a thin wall tube, the one from the 92 Bonneville I saw at the junk yard was around 1/4" believe it or not.
That'* about all I can post in this topic, It apears some are too stubborn to even listen to what I've written anyway.
No one ever said a hollow bar is stronger then a solid bar of the same diameter.
Do you have proof that it is a thin wall tube, the one from the 92 Bonneville I saw at the junk yard was around 1/4" believe it or not.
That'* about all I can post in this topic, It apears some are too stubborn to even listen to what I've written anyway.
05-23-2006, 06:17 AM
#20
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Originally Posted by T-Keith
Guys my math is correct. Look it up, I found the same formula on 5 different website refering directly to sway bar diameters.
No one ever said a hollow bar is stronger then a solid bar of the same diameter.
Do you have proof that it is a thin wall tube, the one from the 92 Bonneville I saw at the junk yard was around 1/4" believe it or not.
That'* about all I can post in this topic, It apears some are too stubborn to even listen to what I've written anyway.
No one ever said a hollow bar is stronger then a solid bar of the same diameter.
Do you have proof that it is a thin wall tube, the one from the 92 Bonneville I saw at the junk yard was around 1/4" believe it or not.
That'* about all I can post in this topic, It apears some are too stubborn to even listen to what I've written anyway.
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