i'm an newbie here

i'm interested in the differences between hollow and solid sway bars in the interest of discussion.

1) can stiffness be measured?
2) is too much stiffness too much?
3) does thickness = stiffness?
4) weight...does it matter?
5) what about materials it is made of. could certain materials be more/less desireable?
6) mounting points...does it matter.
7) adjustability..why would i want it or need it?
8) does a solid bar automatically mean more weight and a hollow bar mean less weight?
9) lets not forget bushings, stiffness, durometer (spelling).
10) combinations of weight, bar stiffness, bushing stiffness, what's desireable?
11) durability of each component?
12) bushing noise?
13) any adverse reactions to the unibody?
14) how does all the above affect handling?

did i miss anything?

why does everything above sound like a **** casting call?

assumptions:
*everyday driving on medium to bad roads. lets be real here, we drive on city/state/federal streets and highways here. not an oval or racetrack. that means, potholes, animals, speedbumps, and my favorite, manhole covers!

*semi agressive driving style... but basically, i'd say most of the people here are stop and go traffic trying to avoid pedestrains.

*stock suspension and stock tires/rims (we'll 15" ones that is)

*almost forgot... this is for a LEXUS sc300/sc400..though would a weight difference matter?

please feel free to post your experiences and opinions.. although i'm not a moderator and i can't edit anyone's text,PLEASE DO NOT USE BRAND NAMES IN YOUR DISCUSSIONS OR EVEN INFER THEM

 

yesYes, you will get wheel lift, also making one set of tires stiffer than the other set will change handling (front/rear) It is a factor Yes it does Yes Stock locations are fine It allows you to tune the handling of your car Generally speaking, yes Those are all factorshttp://www.teamscr.com/sway.htm
http://www.fernblatt.com/longhurst/s...ion_bible.html

 

Yes it can, one method would be to test the transfer of movement from one side of the car to the other. I guess you could accomplish these feat by mounting the bar on the car, then using a fish scale to pull down on the opposite side that is not mounted to the tie end. By measuring the amount of weight required to move each bar 1/2" could be a good measure of stiffness. (I am not a physicist but my brother is, he thinks this will give an excellent read)
Definitely, you want to maximize traction on all four tires without overdoing it. Not to mention balancing ride with performance. This is a Lexus, not a stock car.

Thicker is stiffer because of rotational torque but this is not to say that a thinner, solid bar wouldn't beat a thicker hollow one.

Yes, weight always matters, lighter is better. Both sprung and unsprung weight sucks. Lighter car with a lighter suspension is better. Granted the car weighs 3000+ however, why add more that you do not need to?

Well, different metal has different qualities. So yes, this is important.

Yes it does. If there is a way to get a straighter bar on the car, then it would hold more torque given the same properties.

Every driver, every situation, needs adaptability. Some like more understeer etc.. So adjustable is a huge plus.

Given the same OD, yes.

Stiffer bushings make a difference in forcing the bar to transfer the lateral force. If you had a super soft bushing, then while cornering, the bushing would allow some play before forcing the opposite suspension to compress. So a stiff bar with soft bushings would not be as effective as stiffer bushings.

The optimum is low weight, controllable stiffness, and high durometer bushings. The lower unsprung weight allows for better control.

Long life is a definitely desireable property.

Well, again, this is a Lexus, noise would not be good.

I don't know.

How Stuff Works

Nope

 

stevenem & pcmw-

thanks for your reponses and the links. especially the:
http://www.teamscr.com/sway.htm

which shed a lot of light on this matter in addition to your responses. according to the article, twist or torsional rigidity is:

twist = (2 x torque x length)/(pi x diam^4 x material modulus)

basically as stated in the article, the easiest way to decrease twist is to increase diameter since it's to a power of 4.

the other way to decrease twist is to increase the material modulus (or i think the material modulus of elasticity). i don't have a materials book with me so i don't know how significant this maybe but i'm guessing not much. so assuming 2 bars are made of the same materials with the same outer diameter...but one is hollow and one isn't. the material modulus of the hollow one should be less than the solid but i'm guessing not by much. also, how hollow is hollow? but the hollow bar should definitely be less weight than a solid bar.

by any chance, does anyone know what solid bars are made of and hollow sway bars usually made of?

as food for thought, what about making a hollow bar covered with carbon fiber to increase the material modulus?

what about filling a hollow bar with somekind of foam or insulation dampening material to offset any shock and increase dampening?

what about a sway bar made of entirely composite materials(solid or hollow)? as a possible analogy, if you think about it, tennis rackets once were made of wood, then came the metal ones, then light rigid composite material (carbon, kevlar, graphite, and who knows what else). of course they overdid it with the widebody (which you don't see too much...to much uncontrollable power). golf clubs are the same way... and everything is hollow. this could all be a far fetched analogy...but think about it.

all of this and you still have to think about bushings and it's affect on the sway bar (i don't think the articles said much it but you gave examples).

oh yeah, would the stock end links that connect the sway bar to the lower control arm be able to handle the added stresses?

looking forward to hear anymore opinions/insight to help everyone.

 

a link to help calculate differences between solid and hollow core bars... sorry, can't verify if the calculations ok... it's been awhile since i had do do these type of calcs (i particularly wasn't fond of partial differential equations).

mustang comparisons:
http://personal.riverusers.com/~mira...tang/sway2.htm

fun stuff to read up on:
http://www.aeromech.usyd.edu.au/stru.../Chapter04.doc
http://www.stfx.ca/people/eoguejio/2.../torsional.htm

oh yeah, when i said "the material modulus of the hollow one should be less than the solid but i'm guessing not by much"

it should have been torsional rigidity and not material modulus.