Tandem Suspension Concept

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Originally Posted by roverrescue

I will always run a solid axle on trailers after playing with inde swing arms for a season.
I like the load sharing, stability and constant camber you get from a solid axle.

Tow rig is a 130 with tdslugi motivation - but for the sort of places this thing will go a massey furguson would do the job. Generally our long range trips involve 200km of driving which takes all day to complete!

Brakes will not be electric (waste of time on a boat trailer) and will not be Alko et al cable operated overide (rusty waste of time). I have had good success with commodore calipers (alloy with SS pistons) and a simple over-run hydraulic hitch.
In honesty the brakes will be locked out much of the time as reversing against hydraulic over rides is a joke.

S

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On the Leone 2wd they have the same trailing arm but the pivot mount is a bush and pin set up with a round hollow beam axle between the 2 stubs.

Quite a good set up and I can tell you that it is great on corrugations at speed as A mate had one as a rally car, very strong and great control.

The swing arms are not meant to be welded like that obviously as on the solid beam type they are made from spring steel and provide the flex to the beam.

The 4wd's were fully independent but I wouldn't call the 2wd versions independent rear, more or less 2 link plus shocks and springs on a live hollow beam axle.

When I get the chance I have to build a small light trailer for my old man so I will build it with this type of suspension (but torsion bar for simplicity sake) using Subi arms and see how it goes.

Cheers Casper.

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Originally Posted by roverrescue

Absolutely Ben,


Bill, I would still be interested to learn how you would propose the axle to outer leaf pack connection in a camel back setup. Solid attachment to longest leaf or to multiple leafs thus limiting interleaf sliding.

Steve

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Google can be bloody frustratingly useless at times. I googled and read 30 odd pages of crap on Mack Camel backs to try and findout exactly how they attached the ends of the springs to the axles. It would appear that the ends of the main and second leaves are bent down 90 degrees with a gap between them and these ends sit inside slotted eurathane or rubber isolater bushings that fit inside so called spring boxes at the axles. The only interesting information I got was that for offroad tipper work, Mack owners preferred Camelback suspension to airbags,They claimed the bags were too slow in transferring air from leading to trailing axle and vice versa for proper loadsharing articulation, citing issues of broken diffs and bent axles in addition to poor traction and poor offroad ride as negative side affects.

Instead of clamping the ends of the springs, how about just bolting a spring with standard bushed ends to the axles and use a single upper link to control braking torque ?

I personally can not see the point in single axle boat trailers. They may be ok on road, but with a boat there is too much overhang for offroad.
Bill.

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Originally Posted by wagoo

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I personally can not see the point in single axle boat trailers. They may be ok on road, but with a boat there is too much overhang for offroad.
Bill.

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Tandem axle has the advantages you suggest and allows for more redundancy, however is a lot more weight and rolling resistance to drag around. In my case it also means the difference between brakes and no brakes.


Steve - I have an idea. Instead of the pivoting leaf setup, how about a solid (pivoting) connection between the axles with an (air)spring/shock either end. You could space the springs and shocks up the same as your design. If you use air springs they can be linked on the same side so they can pivot freely.. (clear as mud?)

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Originally Posted by isuzurover

Tandem axle has the advantages you suggest and allows for more redundancy, however is a lot more weight and rolling resistance to drag around. In my case it also means the difference between brakes and no brakes.


Steve - I have an idea. Instead of the pivoting leaf setup, how about a solid (pivoting) connection between the axles with an (air)spring/shock either end. You could space the springs and shocks up the same as your design. If you use air springs they can be linked on the same side so they can pivot freely.. (clear as mud?)

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A solid beam pivoting off the chassis would transmit excessive shock loads to the chassis when both wheels on the same side strike bumps simultaneously. Unless the airbag interconnection transfer hoses are large diameter ,at high speed they might end up behaving similar to separate units, just like the Mack tipper operators discovered when comparing Macks Camelback and AirRide options.
Bill.

Ben, why would it mean the difference between brakes and no brakes?

weight.

This is one suspension set up I think is worth looking at.
Simple, uses one spring and while it will not give out right long suspension travel in a up and down form with load ( I think that would be a good thing for staibility), It will allow good movement of both axles to follow the ground off road.
Could be used with rubber or air bag.
https://www.aulro.com/afvb/

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Originally Posted by 101 Ron

This is one suspension set up I think is worth looking at.
Simple, uses one spring and while it will not give out right long suspension travel in a up and down form with load ( I think that would be a good thing for staibility), It will allow good movement of both axles to follow the ground off road.
Could be used with rubber or air bag.
https://www.aulro.com/afvb/

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With rubber springs that is the Mitchell suspension developed by Bob Mitchell, a former Sandgroper, who designed and prototyped this whilst a development engineer at White Motor Corporation of Australia, late 1970's. He had been playing with the idea for some time before he moved over to Brisbane to work at White. Needs shock absorners as there are no multi leaf springs to provide dampimg action. Also need a means of retaing the sring units in place. Bob used long bolts down the middles. Also requires lateral control by Panhard rod, Watts linkage, A-bracket, etc.

Yes!!!

This is the one I was talking about way back at the start, except I was thinking that it had a single pivot at the time. I thought this was an ARB designed suspension used on the mil tandem trailers????

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Originally Posted by uninformed

Ben, why would it mean the difference between brakes and no brakes?

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Because the registration authorities require brakes on trailers of that capacity.