I've always wondered exactly how much of a difference a solid swaybar makes vs. a hollow one of the same diameter. Of course the wall thickness matters too, but how much of a difference in stiffness would you guys estimate there is? I noticed that the new '06 Civic Si uses a 28mm solid front swaybar while other Civics use a 25.4mm hollow bar (3.5mm wall thickness). This also goes along with a 17% stiffer front spring rate in the Si vs. other coupes. I also know that my Suspension Techniques swaybars at 25.4/19mm are solid and do indeed seem rather stiff for their size. Any ideas? Physics majors? Is there a usable equation for calculating the differences in stiffness between different sizes as well?

 

http://www.whiteline.com.au/do...r.pdf

 

I think the science of swaps bars is a bit beyond most of us fully comprehending. The more i learn about suspension the less i really know. But thinks to consider as variables in the bars are.
Steel or aluminum?
hallow or solid?
wall thickness.
And the length or the TQ arms on the bar.
Note that adjustable bars simply have diffrent holes drilled in the arms so you can change the stiffness. Considering these variabeles i dont see how you could say bar X is going to be stiffer than bar Y based simply on hallow or soild and wall thickness. Those TQ arms play a big role in the equation. All that is just for bar stiffness, but to consider the effective bar stiffness you might want to look at the mounting points and concern your self with the bar to wheel motion ratio and how you could use diffrent pick up points are bar lengths to change that rate. So in theroy you could use a stock bar and just drill a hole closer in on the TQ arm and make if effectly stiffer just by changing where the end link connects. Now i am going to check out tysons link and see how fucked up my post is.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ohjolt2 &raquo;</TD></TR><TR><TD CLASS="quote"> Now i am going to check out tysons link and see how fucked up my post is.</TD></TR></TABLE>

lol, getting much sleep over there, soldier?

spelling is a bitch...


anyway, yeah, there are MANY more factors in designing a sway bar than hollow or solid. i would hope this original question is not trying to directly compare swaybars from two different chassis, but just in general theory. the article speaks directly towards the difference of hollow and solid bars.

btw, not ALL swaybars are adjustable only by the torque arm length adjustment of the endlink. one way is to start out with a straight hollow bar, and then adjust the wall thickness by replacing the bar.

http://www.1speedway.com/Swaybars.htm

there are other ways too. comptech has their own way of using two concentric bars and connecting them in the middle at different locations.

then remotely adjustable swaybars use rectangular torque arms that you rotate. like bending a 2x4 beam, rotate it 90 degress the stiffness changes.

 

also keep in mind the number of/shape of the bends in the bar changes the stiffness as well.

 

Thanks a lot guys. That link was great. Yup as I thought, swaybars are freaking complicated hehe. I guess all you can do is try different ones out until you find one that fits your needs, and bar diameter can be used as a (very) general guide.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bad-monkey &raquo;</TD></TR><TR><TD CLASS="quote">also keep in mind the number of/shape of the bends in the bar changes the stiffness as well.</TD></TR></TABLE>

I would like to add that swaybar materials is also a factor. They can be made up of 4130 heat treated or 1018 cold rolled, and the stiffness may vary greatly. Anyone know what material the factory uses for their swaybars? or aftermarket?

Charleston

 

I've heard varying things about hot rolled or cold rolled bars/metal. It was presented to me as such: If they 'bent' the bar cold, what prevents it from bending in normal use?

If a bar was bent hot, then it won't get bent under non-hot use. But at the same time, i've read that heat can compromise the integrity of the steel....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ohjolt2 &raquo;</TD></TR><TR><TD CLASS="quote">I think the science of swaps bars is a bit beyond most of us fully comprehending. The more i learn about suspension the less i really know.</TD></TR></TABLE>
Dude marines are marines, soliders are in the army. I am a marine but an army guy isnt an army. Honestly if any of you knew how much sand and coffe and crap was in this keyboard you would all puke, Its like a freaking 100 year old typewriter. You got to beat ths **** out the keys.