Rear swaybars for off-road use

[Ol'fogasaurus]

I have moved some of the information that was miss-posted (by me mostly) from http://www.shoptalkforums.com/viewtopic ... 8&t=149626 which was on Axle Clips. The information was somewhat allied but I feel should be a topic in and of itself. One of the reasons I moved this to its own string is for keeping the first subject intact but also to make this a more searchable single topic just-in-case someone needs the information.

"This morning on the Power block Extreme Off-road show they were again working on the trailing arm jeep that I referred to earlier but this time they were talking about gas/hydraulic bump stops, reasons to use and how to fit them.

It is the same build as when they were talking about what I knew as a "walking sway bar" which is the same thing as Dan was talking about on his race car but using a different name for it. Again, it is for trailing arm suspensions and having loads work back and forth between the two trailing arms.

http://www.offroad-engineering.com/cuswbarkit.html

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Other than the torsion bar sits free connected to the two arms and is not pinned to anything, this is kind of what I was talking about.

I wonder something like a Watts Linkage couldn't be fit somehow to eliminate side to side motion of the trailing arms.
Lee

What do you mean by not pinned to anything? Here is a sample of one I am much more familiar with

http://i65.tinypic.com/2yn461l.jpg

http://i64.tinypic.com/2mp0pkw.jpg
CentralWAbaja

If the torsion bar is sitting free, not attached to anything (like the front BJ sway bar is) but the arms then yes I think that is what I have seen and what I think that is what Dan showed in his picture (remember, my memory, at least for words, isn't what it used to be at times). I don't remember his arms being real long but it has been a while also since I saw them.

This has come up a couple of times now but the best picture I think were from Dan at Dansparts.

http://www.shoptalkforums.com/viewtopic ... y&start=75

See page 6 mostly (I've copied the pictures but you will have to go through them. There are at least 4 that show the sway bar he is talking about.

Some more update pictures as I'm getting the final assembly done.

I hope this helps some.

Lee
Update:

Looking at it again the torsion bar looks to be held in place which makes sense since the joins to the arms of the sway bar and the trailing arms have pivots in the spherical rod ends. My bad!
Lee

The pics I posted are of my car Lee. Thought it showed the whole package pretty good.
CentralWAbaja

If the torsion bar is sitting free, not attached to anything (like the front BJ sway bar is) but the arms then yes I think that is what I have seen and what I think that is what Dan showed in his picture (remember, my memory, at least for words, isn't what it used to be at times). I don't remember his arms being real long but it has been a while also since I saw them.

This has come up a couple of times now but the best picture I think were from Dan at Dansparts.

http://www.shoptalkforums.com/viewtopic ... y&start=75

See page 6 mostly (I've copied the pictures but you will have to go through them. There are at least 4 that show the sway bar he is talking about.

Some more update pictures as I'm getting the final assembly done.












I hope this helps some.

Lee

Update:

Looking at it again the torsion bar looks to be held in place which makes sense since the joins to the arms of the sway bar and the trailing arms have pivots in the spherical rod ends. My bad!\

Lee

What I was showing was Dan's car which is the one I remembered. I must have missed seeing the triangle mount w/tube that it looks like the sway bar is probably riding in. Not arguing just trying to be clear in what I was talking about and make sure I was right... or in this case wrong . I seem to remember that there was another picture Dan posted which got me thinking that the sway bar was sitting free not sleeved. Too long ago since I had seen it I guess .

Lee"

[Ol'fogasaurus]

http://theoldmotor.com/?p=20330

Seeing what the sway bars looked like in Dan’s first post I think this is got me off on the wrong track on remembering the trailing arm sway bar: this is a picture of a Sixteen-Valve Duesenberg Walking Beam Engine. The beam, aka walking beam engines I find fascinating for some reason. https://en.wikipedia.org/wiki/Beam_engine

Just for the fun of it:

https://www.youtube.com/watch?v=pUDQYzE9gcM This is a video of a working (operating w/o steam) steam walking beam engine.

Lee

[CentralWAbaja]

Did they have sway bars on that steam engine

In trying to add to this topic and post pics of mine

[jg210302]

How did you guys determine the size and effective "Rate" of the bar?

[Ol'fogasaurus]

It looks like I am going through another period of not being able to post here. Lets try it again:

A few weeks ago Spike TV's Extreme off-road had a show where the first part of the show was talking and showing the building of a off-road trailing arm conversion to a Bronco they are building. The sway bar arms were on the torsion bar and sitting in a tube but the rest of it wasn't there. Here is the URL for it: https://www.powernationtv.com/episode/X ... o-sway-bar I don't remember him giving info how to figure the torsion bar and the this part of the build is incomplete. I think I would make a call to Dan's Performance Parts (http://www.dansperformanceparts.com/) and ask some questions. Their URL doesn't talk about them but they have one on at least one of their race cars.

When he first talked about it I did not understand until he posted pictures. A unique design and very ingenious idea. I think he is on Facebook also. I sure would like him to start posting here again; a lot of good information.

[CentralWAbaja]

How did you guys determine the size and effective "Rate" of the bar?

Best kept secret in all of off-roading Nobody wants to share

[CentralWAbaja]

Actually I used numbers from a few guys from here that are running them...and have broke them. I also used a friends numbers off his V8 Tatum sand car. They all gave me measurements and then I did a lot....a lot....did I say a lot???? of math. Speedway Engineering had the bars with a very complete spring rate chart. I basically converted everybody's setup to spring rates and then I tried to pick the longest bar I could fit in and went with a .188 wall thickness so that it was in the middle of the bars to choose from. I could go up to .250 wall or solid or down to .120 or .095 wall. I then adjusted my arm length to get in the ballpark with the others that I had for reference as far as the spring rate. I then moved to live mock up with a couple of wooden arms and adjustable links to decide where to place bar and links ect. Now we can go into rising rates of the springs and all of that but really I am not that good at math and forget stuff faster then I used to so really this is a long way of saying its was all an educated guess.

[Ol'fogasaurus]

Very good information Darron. I suspected that educated guesses would still be in the play on this as there is so much to consider and the idea seems to be so new; weight, length of travel (adjustable mounting location, arm length/pivot location, torsion bar torsional limitations, spring rates, etc.) and I am sure there are a lot of other things in the mix.

[Ol'fogasaurus]

Darron, I guess I didn't know that you have the rear sway bars. I guess you are now the Goo-roo on them here.

[jg210302]

Thanks for the info Darron! I was always curios about that... I wonder if anyone has done a blade style adjuster, back in my Indy car days that was how they were adjusted.

[dustymojave]

The blade being the arm on the end of the sway bar. The "blade" is made of flat plate that if it's vertical, it transmits a lot of leverage, if it's rotated flat, it flexes and reduces the amount of leverage transmitted. They were real popular in road racing cars in the 80s. I prefer older school sliding clamp types for adjustment. Short track circle racers are more inclined to use a heavy bar with a series of holes for adjustment.