3-4 Link Suspension?

[ExpoMike]

What I was thinking in terms of. Much simpler to execute using far more off the shelf parts that can be found at most any trailer supply house or parts house. Wouldn't be ITS, but that didn't sound like it was a goal. Using only the main leaf keeps the base spring rate low. Were it an off road race car this would create a damping nightmare, but for a trailer it shouldn't be a problem.

I have been toying with this idea as well as the one above. My Kamparoo is using slider springs with shock and though it worked very well this past weekend on the Mojave Road, I could see it having a little bounce while on the freeways. I also would like to give a little more isolation to the chassis when traveling over rough or washboard type roads. By getting airbags into the mix would greatly help with those and add the ability to adjust for loads, I really found that I did not need an independent suspension setup. I even did not need anymore clearance and was quite surprise by how great it worked offroad.

I have also thought about quarter elipical spring setup, using just the front half of the spring to locate fore and aft location with a panhard bar for side to side. Airbags for height.

Hummm.... lots of ideas. :ylsmoke:

 

[ntsqd]

The one thing that trailers mostly lack are shock absorbers. What ever is done they should be high on the importance scale.
Even though they work, I dislike 1/4 elliptic leaf spring lay-outs. While simple and with few failure modes, most of those failures stop you where ever you are. With a semi-elliptic most failures still offer a limp-home mode.

On the stub idea I mentioned, I guess technically you could call it a square - especially if poorly executed. However, if it is done right - that being that the converging tube is partly coped to the linear tube at the junction - then you're only doing part of the long cope. Think of the stub tube as a buttress.
Square stock would still have the long cut, just easier to do.

 

[Section 8]

Odd trailer suspension; twin I-beam-ish:

 

[Tucson T4R]

Odd trailer suspension; twin I-beam-ish:

Wow, what kind of trailer is that suspension on? Looks pretty rugged.

 

[archtimb]

Yes, very interesting. More info or pictures?

Mitch

 

[Dave]

Yes, very interesting. More info or pictures?

Mitch

http://www.tracktrailer.com/Traveller Web Gallery/

http://www.tracktrailer.com/

 

[archtimb]

Thanks!
I knew about the trailer, I guess I just had not drilled in deep enough. Anybody have experience with this style suspension? Looks like those bushings would take a beating on washboards.

Mitch

 

[ntsqd]

No more so than the radius arm bushes used in Ford's TTB/TIB & older 1/2ton live axle front suspensions. A lesson learned on a Stock Full desert race truck is that urethane is far less long-lived in that application than is rubber.

 

[ckkone]

I have a large collection of trailer suspension images here

I like the look of this one, the spring could easily be swapped for an airbag.

 

[TheGillz]

You suspention heads might find these pics interesting....

http://www.offroadevolution.com/images/EVO_LEVER.pdf

 

[Grim Reaper]

Ok, I played with this idea and came up with....

That's in line with what I have been thinking about doing. Simplicity at its best. Easily adjusted to make sure it tracks square.
The track bar should be closer to level but other wise pretty well what I was thinking of doing. Not quite as good as the AT independent but WAY better then leaf springs.

 

[GeoTracker90]

That's in line with what I have been thinking about doing. Simplicity at its best. Easily adjusted to make sure it tracks square.
The track bar should be closer to level but other wise pretty well what I was thinking of doing. Not quite as good as the AT independent but WAY better then leaf springs.

Yeah, I just kinda threw this together and just placed the trac bar out in space. You could box in the back of the trailing arm mount and place the track bar mount up near the top of that. Then you could have a drop bracket on the frame to get the bar either level or close to level. Add adjustable links on the frame side of the two trailing arms and the track bar and Bob's your Uncle!

Mike

 

[ntsqd]

You suspention heads might find these pics interesting....

http://www.offroadevolution.com/images/EVO_LEVER.pdf

That's been done, and done, and done, and.........

It can be made to work semi-OK, but it will never be a great design until someone works out how to not have the rocker end of the damper travel in a small radius arc. The problem is that damping & spring rate change radically depending on where the rocker arm is in it's arc of travel due to the large change in effective lever length. If too much ratio (shorter damper stroke than travel) is built into the rocker arm then damper piston speed falls off. That is counter to what a deflective disc type damper (what they're using) wants. Deflective disc damping works best and is the easiest to tune at close to 1:1 wheel travel to damper stroke.
Why a typical linked race truck rear works is that the lever length to damper stroke ratio is large enough that the leverage basically doesn't change through-out the damper's stroke. As a real rough estimate the lever's pivot to damper mounting point distance needs to be about twice the damper's stroke. In their rocker arm they've got just about the inverse ratio.

On a trailer all of this may not matter. Dunno......

 

[Grim Reaper]

Three link in a box.
http://www.trail-gear.com/trail-link.html
You can buy the parts you want separately

 

[ExpoMike]

Three link in a box.
http://www.trail-gear.com/trail-link.html
You can buy the parts you want separately

Cool kit but for $1100, way too much overkill for a trailer. One of the biggest things trailers don't have to worry about is pinion angle. With the above kit, it helps keep the pinion angle correct while traveling through the range of motion.

Have watched our trailer behind us, don't worry so much about the suspension having much rotational articulation as it pivots on the front coupling and the whole trailer will rotate. The bigger concern is up and down travel. This is what will soak up the bumps and washboards while driving. Even driving behind an AT trailer with its independent suspension, I never saw the trailer really have any rotational articulation as the trailer would just lean over. What I did see was that on the washboard road it would not "hop" like my standard leaf spring setup.

My .02 worth. :ylsmoke: