Thread: Independent Suspension Design

Please dont get me wrong David,
In no way am I telling you to suck eggs!
I will shout you beers when you end up passing through Cooktown
I love the fact you started, carried through and completed this project.
Way too many people would have just copied Kimberleery etal inadequate swing arm suspension design.
You went and played with a design that you thought up AND that should be totally rewarded!

I guess it is more that I have played the single axle independent trailer suspension game and in my opinion (as Sitec mentions) independent is a bad joke being played on everyone who buys into it A trailer is a tripod. There is absolutely no reason to have independent suspension and independent loses left-right dynamic load sharing.

I personally think swing arms have become popular because they are sexy.
AFAIK SugarGlider started it. In the 80s they were able to package swing arms for any dimension trailer with coils (unheard of in toyota land when leaves ruled) and the setup is compact.

Offroad trailers in my opinion do need to track the same as the tow vehicle - so if you are making generic suspension for trailer manufactirers swing arms are easy as you just bolt/weld them on at the correct width.

But it is also my opinion that trailers must have left right dynamic load sharing for stability on broken ground.

So if you run swing arms (especially on soft spring rates ) then you really need to link left to right with sway bars

Or you could just run a solid axle and any other combination of links. Radius arms with panhard, triangulated four link or parralel four link with panhard, or follow TrackTrailer and run cross arms as your main links and then single pivot radius arms.

David,
I am very keen to see how you set up the antirock/ARB units and if they fix the twitches...

Out of interest would your current chassis design allow some parrallel links to be mounted on the main cross bar that leads the wheel well?
Potentially if that cross bar is structural or can be tied in so it is, you could run parralel lowers from them back to a solid axle and then run triangulating uppers from you current leading bushes?

The first (and last) independent single axle I built was on a gal dipped chassis.
The suspension sucked badly in dynamic situations and wrt to tyre wear.
It was a fiddle but i was able to manipulate the existing galvanized swing arm pivot connections to accept a triangulated four link design.
That trailer is now 3 years old and going strong.
Obviously not perfect as I had to work with an already galvanised setup
But MkII happens to be a chassis Im laying out in the shed at the moment... this one is a chassis for a camper trailer (the original above was a boat trailer)

I have a .DXF for the rough design when I get my act together Ill take some purdie pictures and post a build in AULRO.


Peace (and there are cold beers in fridge for ya David)

Steve

Righto that beer will be called for when i eventually do the Cape

Steve, when i started having problems with the boat effects of the suspension i looked back through the posts & found your post about the sway bar. I have a number of very experienced suspension mates, two are from the off road racing arena that backed your idea with a very good explanation which eased my miss understanding of the sway bar.
I appreciate all members & mates giving me their thoughts & ideas on most things that i build as i'm no a no it all, so i take all comments on board.

Thanks for your help as it has helped, keep them coming.

David

If you have bought the antirock gear then cest la vie
but if not perhaps think about a suspension re-design???
A solid axle with triangulated fourlink on that chassis with those springs and dampers should work nicely.

Airbags and dampers locations will not need to change.
Your bomber axle tubes can remain and most of the swing arm material can be incorporated?
(just a note I am going to emulate your sleeving and welding technique for the flange/ stub axles on this new build)

With the triangulated fourlink, I went with a stepped axle (65 SHS 6)
The step in the middle could be accused of being done to give more clearance but really it gives verticle separartion of the upper links from the parrallel lowers.

Anyways - keep the good build going!!!!

S

My Antirock Kit has arrived today
So Saturday ill be trying the install i'm hoping.

Cheers
David

Made a start on the Antirock Kit.

Got the front mounts fabricated & bolted in position, next Saturday we will get the other mounts & hangers in position ready for testing.

Cheers
David

Finished the setup tonight.

Got everything together, this thing works really great, it has reduced the body roll massively. I will need to do some fine tuning through the week, very happy with the kit.
I will post some images real soon.

Cheers
David

Ok some images, now this is not complete as everything needs cleaning up before going to the powder coating.

Cheers
David

When you go on the corrugations those antirock ball ends are going to get a right beating ! A good few years back now some guys from LROC WA built a fuel carrying trailer for a Canning trip they did, that was coil , might be some info on that they had quite a few interesting tech problems but got it sorted in the end IIRC