3/4-Link & Integrated Anit-Swaybar Design?

[JESSE_at_TLT]

I was thinking about different ways to incorporate an anti-swaybar into a 3/4-Link suspension design. Has anyone used a torsion-bar to connect the lower-links where they pivot at the frame? It seems like it would be a compact design and eliminate some moving parts/linkage. The only downside I can see is that the splined lower-link pivots wouldn't tolerate much misalignment. I'm sure some people have played around with this. Anyone?

[matt_helton]

i dont know about that but someone has a TT that has a sway bar mounted on the axle and connected to the lower trailing arms with small links. i remember a picture but cant find it now.

[ALEX]

Here's what matt was referring to. These pics from the Herder TT in the Skunkz section.
http://www.race-dezert.com/skunkz/newline_herder/16.jpg
http://www.race-dezert.com/skunkz/newline_herder/15.jpg
http://www.race-dezert.com/skunkz/newline_herder/18.jpg

I heard the baldwin TT's had a sway bar integrated into their cantilever arm mounts?

[ntsqd]

For a straight torsion bar to work you'd likely have to slightly compromise the linkage geometry to clear the driveshaft with the bar. Doing it this way turns the lower links into levers, long ones at that. The bar would need to have a very large OD if it is to provide much roll rate.

GM did something like the Herder pics starting in '64 (?) on their 'A' body cars. In their case the bar bolts to the side of each lower arm with two bolts per side.

P.S. Say hello to Trevor Huiskens.

[FullsizeFun]

I like to see things like that cuz they are different, but 2 things I see is that design (on the axle) would add to unsprung weight, though not by much, and it is also in the way if you needed to change the diff in a hurry.

[singlehanded]

Who built that sway bars?

[Greg]

Crawl under any mustang from 79-present, they mount the sway bar on the lower links. Works like crap too. Older vw cars (sciroco and rabbit) used a "torq tube" where the to trailing links were attached by a big tube that would twist and that was the primary torsion bar. You ever see the inside rear wheel of those cars off the ground, worked pretty good, but the tube was HUGE compared to a convetion sway bar.
Anyway, who needs sway bars, ha.

[JESSE_at_TLT]

Alex-
Thanks for the pictures of the Herder TT setup. It makes for easy mounting, but why add the unsprung weight to the axle assembly? I guess it's probably not that big of a deal.

The Baldwin TT uses a torsion bar to connect the cantilever arms and the 7 Open Ranger that Mike Normile is building has a similar torsion bar/cantilever swaybar setup. I think those trucks are pretty slick, but they're both also pretty complicated designs with a lot of moving parts.

ntsqd-
What are you thoughts about the potential driveshaft interference and the diameter of the torsion bar to control levers as long as the lower links? Why wouldn't it work just as well? It seems like the main advantage might be in the easy packaging any elimination of additional moving parts. Oh, and how do you know Trevor?

[ntsqd]

My thinking is that potentially the lower link frame pivots will want to be in a place where a straight tube/bar connecting them will intersect the trans or driveshaft. With the long lower link as the lever arm the OD of the sway bar (now most likely a tube) will need to be rather large for it to have any effect. The closer you get the driving point of the bar to the axle, the smaller the OD of the bar for a given roll spring rate.

You could easily do something like the Herder set-up, only at the frame end instead of the axle end of lower links. Using short toggle links to drive the sway bar removes the splines from needing misalignment capability. That puts the bar where you want it for packaging while relieving some of the design complexity of the frame pivots and reducing unsprung weight. Note that the bar does not need to be exactly on the frame pivot axis, it could be to the rear of it. Conceivably you could fab the lower arms to bolt a Toyota torsion bar socket onto their inside surfaces and run a splined bar btwn them. I'd guess a Toyota torsion bar to be too long, but a custom length bar shouldn't be too hard to have made. I don't know whether you could get enough roll spring rate from such a set-up, but the design concept is very feasible.

Reducing unsprung weight is worth doing. Not as much as it is on a road race vehicle, but it's still worth it.

I went to Chico State with Trevor, ask him about the "Cruiser Classic" trip in his bus & tell him I still remember his 256 final presentation. LOL