Sway bars/ torsion bars? Anyone have one on their rod?

[CORPO]

I was looking at this modifiable sway bar kit, wondering if anyone has used this kit... or if any one knows of other kits like this out there?

http://www.welderseries.com/blog/online-store/sway-bar-kit/

Im just thinking ahead, I want to drive the wheels off my truck when its done, and I think having the air bags on all four corners, I might have more body roll than I want...

 

[CORPO]

I was not thinking, I should have put this under the frame/suspension section...

 

[forbigpicture]

Corpo..........DJ3100 used this set up on his 55 wagon might check with him..
I'm also looking into this for one of mine....

 

[rvreddog]

I took toyota torsion bars and turned them into sway bars for my wifes rock buggy.

 

[sneakysnake]

Be sure to run each bag on a valve, don't "T" the air lines this will help a whole lot.I'm running a bar on the front of mine but I really don't think its heavy enough to sway much even if it was off.

 

[Skip]

That's kind of interesting. Of course I used 4-door blazer front and rear sway bars on the S10 frame under my 38. Should handle nice.

 

[CORPO]

Corpo..........DJ3100 used this set up on his 55 wagon might check with him..
I'm also looking into this for one of mine....

I knew I saw this kit somewhere..

Be sure to run each bag on a valve, don't "T" the air lines this will help a whole lot.I'm running a bar on the front of mine but I really don't think its heavy enough to sway much even if it was off.

got that covered, I have independent 4 corner control, no shared valves.. im just a little concerned about body roll, or having to increase the pressure to stiffen the bags to the point where its sitting up at full inflate

 

[jfg455]

yes. I alway put a sway bar in even if it has to be hidden some how. A lot of times I will get a used sprint car or stock car splined shaft and ends off of ebay. The 1" adjustable unit in the back of my Datsun was $100 total with mounts and links. Only draw back is you will have to figure the tension, bar size, width etc you need and wait for one to come up.

 

[Sam_Fear]

I had to remove the swaybar on my Olds (85 Cutlass frame/suspension) - and no front shocks. 4 Independent bags. I don't really have too much roll, but then I don't really corner hard in it - it's a cruiser.

 

[Neverdone]

I have been wondering about something like this to go on to my 54. Racing neighbor says that I won't need one and his buddy says that I won't want one either....

 

[CORPO]

My problem is ... I went with the "form over function" on my air bag placement on the front, they are probably closer together than they should be ...

I'm mostly just thinking ahead, maybe it won't be a problem! But if it is I will have a plan in my head to fix it... I have a lot of stuff going on in the front so placement will be tricky but I'm sure I can figure something out...

Jfg... I will take a look at the sprint car set ups... Thanks for the tip!

 

[bob w]

http://www.schroedersteering.com/SwayBarPage.html

I tried to figure out correct sway bars for the Fiat when I built it. Looked at Autocross information and the best I could come up with is the sway bar should have about half the spring rate of the spring on that corner. So far, I have not installed sway bars on it so I cannot provide any first hand experience.

I installed a Chris Alston drag race sway bar on the back of my Anglia because of body lean caused by soft coilovers mounted pretty close together. It stopped the roll but it is way too stiff. I think if I tried hard cornering I'd get in trouble because it would lift the inside wheel off the ground. I'm guessing the Welder's Series is pretty stiff too.

It would be nice if an expert would add to this thread.

 

[CORPO]

thanks for chiming in Bob your insight is always valuable.

seems like its kinda a cr*p shoot, on sizing, and rates especially when I have air bags and therefore adjustable ride and spring rates. I would also think that whatever rate you chose on the bar is going to be affected by the lengths of the arms..

The plan as of now, will be to finish it up and determine if it is a problem. But I do think I would prefer too hard of a suspension over a soft suspension with body roll.

But Hey.. maybe it will be perfect and drive like a new Corvette.. ya never know

if anyone else has experience with sizing and installing torsion bars please chime in.. I know we have a bunch of circle track guys on here.. they must have some input

 

[jfg455]

Sway bars are not confusing at all when you look at them for what they are. A spring. All it does is combat the weight transfer from one side of the car to the other when you enter a turn. You can run without sway bars by just upping the spring rate but then you get a harsher ride. You can use softer springs with a bigger sway to reduce body roll without sacrificing ride harshness.

Where they become a neccesity is when you run a traverse spring, air bags that are connected by a tee or are mounted to far inboard. The air bags on a tee just transfers the air from one bag to the other when body roll is induced. Traverse springs pivot on the mount which is in the center of the car. Same pricipal for the air bags or springs too far inboard.

The length of the arm or fulcrum of the bar effects stiffness as well. Mounting the bar to the boddy with links to the axle will reduce unsprung weight as well as helps to hide the bar. Clear as mud? [cl

 

[CORPO]

I fully understand the concept and how it works... It's just a confusion on how to appropriately size the torsion bar and the stiffness..

 

[jfg455]

Maybe how I said it came out wrong Corpo. I meant that the sway bar can be rated like a spring and aftermarket or race style units are often rated in pounds/inch like a spring. Usually with a 1 foot fulcrum (bar end) so a 600 lbs/in bar with a 1' arm would take 600lbs to bend the arm 1". You would have to remember there is another arm on the other side so the effective rate at each wheel is 1/2 or 300 lbs/in at each wheel. The longer the arm the less effective the same bar diameter is.

If you want to use the engineers formula for a solid steel bar then you can use this to get you close. (Ignore the commas in the formula. It wouldn't post with spaces there. grrr)

Formula for sway bar stiffness of a solid steel bar

* ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,500,000 D^4
*K (lbs/in) = --------------------------------------------
* ,,,,,,,,,,,,,,,,,(0.4244 x A^2 x B) + (0.2264 x C^3)
*
*
* B
* ,,,,,,,---------------------
* A,|,,/,,,,,,,,,,,,,,,,,,,,,,,,,\ C
* ,,,|,/,,,,,,,,,,,,,,,,,,,,,,,,,,,\

A - Length of end perpendicular to B (torque arm - inches)
B - Length of center section (inches)
C - Length of end (inches)
D - Diameter bar (inches)

Here is an online calculator as well.

http://www.speed-wiz.com/calculations/suspension/anti-roll-bar-calculation.htm

Here is an example of an aftermarket race style bar that you can adapt easily.

http://www.rjracecars.com/QuarterMax-AntiRoll-Bar-Kit-301195x-Prodview.html

 

[sneakysnake]

I was doing good until we got to the math part.

 

[Skip]

I was doing good until we got to the math part.

That's what happened to me in Engineering School!