Tubular strut braces and anti sway bars?

[98spyderboost]

Long story short. I have the ability and the knowhow to make strut tower braces and anti sway bars out of tube steel. I dont know much about suspensions yet but I have designed all the equipment need using tube rather than solid like the ebay parts.

Question is, What will the different effects between using tubes as aposed to solid braces.

If tubes are better then what type/size do you find is the best custom made tubular setup?
Rigid pipe? galvanized? Aluminized?
All around that is.

Thanks for the recommendations.

 

[MNGSX]

For anti-roll bars use a solid bar.

For STB's hollow is fine. They really get pulled on at the ends as opposed to being compressed.

 

[Jehu]

For anti-roll bars use a solid bar.

Why? What's important in anti-roll bars is bend resistance anyway, and if he's using a thick wall tube like a Sched. 80 tube, the solid bar won't gain him that much increase in the moment of inertia of the bar.

 

[Defiant]

Why? What's important in anti-roll bars is bend resistance anyway,

Not bending, twisting. Do the math on twisting tubes versus twisting bars and you'll see. Anti-sway bars usually have to deal with a few corners in the bargain, as well. Tubing is almost never used for sways.

 

[Jehu]

You're absolutely right...it's twisting...I wasn't thinking . Regardless, polar moment of inertia is radius^4...it's even more accentuated by material far from the center. I suspect sway bars are usually made out of bar because it's easier to twist cars into the funny shapes required for sway bars without collapsing a tubining. Typically in tension and shear, strength/weight of bars > tube. In twisting and bending, strength/weight of bars < tube.

 

[ACM]

Almost all "serious" anti-roll bars (aka swaybar, misnomer) are tubular.

The centre of an anti-roll bar contributes almost nothing to the stiffness, the only reason solid bar is used is for cost and convenience. The math is actually quite specific and clear on this, and most of the decent racecar prep books show the math behind this.

Charles

Ooops - guess I'm just repeating what's been said, apologies.

 

[jtmcinder]

Yep. Torsional stiffness is proportional to the fourth power of diameter. The center of a sway-bar just adds weight.

STBs, on the other hand, can be made any way you wish with no effect.

- Jtoby

 

[98spyderboost]

Thanks for all your opinions. Mr. Wizard taught us that tubes are much stronger, when it comes to actually bending than solid bars. The twisting effect you mentioned is interesting tho. Think I will do some more reading...

 

[MNGSX]

Bending a hollow tube to match the stock path may be difficult.. It may kink, colapse etc..

Honestly the best roll bar design are these.

http://www.chassisengineering.com/pdfcatalog/locators&antirollbars.pdf

28" to 24" of straight tubing, CNC'd end brackets, heim end sway bar links.

That top gun is so stiff it is crazy. How do you think 1.5k+ hp RWD cars keep the chassis level under the TQ of launch?


The best front STB will triangulate to the fire wall (which is why some classes outlaw that type).