Who has shocks on their leaf spring camper?

[walker]

I would like to add shocks to the off-road trailer I am building. From the info I have read so far the angle of the shock is very very important. Problem is I know it is important but I have no idea what the optimum angle is.

If anyone has them on thier trailer would you be able to measure the angle for me.

I would imagine that shocks for a leaf spring would be a lot different to shocks for a coil spring, is this correct?

[hiline]

adam my mate has a new jayco outback camper i could get a pic for you
and i'm sure we could work out the angle as well

[Michael2]

I'm told that the best angle for mounting shocks is vertical, just like the front axle on a Land Rover.

Coils will need double acting shocks, whereas you could probably use series Land Rover shocks on a leaf sprung trailer.

I bought a leaf sprung trailer a few years ago for $52. It had Land Rover size rims with 7.50x16 tyres, but smaller wheel nuts that had RH thread on one side and LH thread on the other. The hubs have grease nipples, the chassis is C channel with large circular holes cut out (like an aircraft frame) and there are round cylinders that take oil and have an arm attached to the chassis and the arm connects to an attachment on the axle - some sort of WWII era shock absorber by the look of it. The arms have been bent back so they don't connect.

I've replaced the wheel studs with SIII Land Rover studs and plan on seeing if I get get the primitive shocks to work. Otherwise I'll be putting shocks on the trailer, it's okay on the road, but I imagine offroad all the conents would go flying.

I mention my trailer design for 2 reasons :

1. does anyone know what it might be off?
2. if you put shocks on yours, I'll be interested in your findings before I put some on mine.

[walker]

I gussed the vertical was probably best, but it is not practica on a normal trailer as the shocks would be very short and I don't know if you could get them short enough.

I would not use standard shocks as they would fade in the first 10min once you hit the corrugations in the outback.

I will probably use tough dog shocks as this is what I have on the Disco and they have worked well so far.

I have looked at a few pics of leaf spring trailers with shocks and they seem to be on about a 45degree angle. One site stated that the angle was of the "utmost" importance...but then never said what that angle should be.

[walker]

adam my mate has a new jayco outback camper i could get a pic for you
and i'm sure we could work out the angle as well


That would be great Ray.

[George130]

I have a pair of air shocks for when I do the trailer. No idea on the mounting yet.

[Michael2]

What about airbags?

Just an idea.

[walker]

What about airbags?




Just an idea.


No, now you are just changing the subject! :p

I already have the axle and springs ready to install, I just need to work out shocks.

[hiline]

That would be great Ray.

I'll get them for you tomorrow arvo

[walker]

That would be aswome. Also maybe a pic of how they are mounted .

I am thinking probably welding a mounting plate onto the leaf plate like this.

https://www.aulro.com/afvb/

[hiline]

i will get pics of the whole set up for you

[Buggerluggs]

Adam,

Back in my Ford days we used to put shockers as vertical as possible. The point to remember is that the more angled they are the stiffer they need to be to be effective. If you look at some of the older wagons such as a Kingswood or old Falcon you will see they are angled inwards. This also assists to a degree in roll stiffness, but not much. It's all about package constraints. You also need to put the lower mount as far out as possible. If you look at the Disco the lower mount is on a bracket mounted rite out by the wheel and well below the axle tube. This is to assist in getting it as verticle as possible. Do something similar and get the maximum out of your shocks.

You definately need double acting, and to stop/minimise spring wind-up under braking (I assume you are going for a braked trailer?) then stagger the axle mounts, one in front the other in the rear.

Just a question, what springs are you going to use? You need to get the longest possible and with very wide leaves. This will allow much greater articulation and the additional width will reduce the stresses and hence spring sag. I would be looking at the Falcon ute with the maximum rating. From memory these are the longest available and will carry about 1.2t, give about 12" of travel and are designed very conservatively (stress levels). If you need to carry more load then add air bags over the springs so you can adjust to the load variations likely.

[hiline]

http://i99.photobucket.com/albums/l295/hiline_01/Picture023.jpg

http://i99.photobucket.com/albums/l295/hiline_01/Picture021.jpg

http://i99.photobucket.com/albums/l295/hiline_01/Picture019.jpg

http://i99.photobucket.com/albums/l295/hiline_01/Picture018.jpg

hope this help Adam

i did try find the name of the shocks but no go sorry

[George130]

That would be aswome. Also maybe a pic of how they are mounted .

I am thinking probably welding a mounting plate onto the leaf plate like this.

http://www.vehiclecomponents.com.au/gallery/608/at608%20all%20terrain%20suspension.jpg

The trailer I got my shocks from was done like that and the welds had broken. I would if you can set it up like on the photos Highlin posted.

[walker]

Thanks Ray, the pics you took were almost exactly as I imagined I would do it but will help a lot.

Ian, I understand what you are saying about mounting the shocks out as far as possible but I think I will be forced to put them on the iside of the spring as it is in the pics Ray put up. This is because the wheel will be too close to the body to fit a shock in there.

I have used off-road springs from a specialist spring maker in S.A. (industrialsprings.com.au). I did want to go as long as possible but it was the weight of the trailer (or lack of it) which limited what I bought. The problem was that the trailer is only going to weigh less than 700kg fully loaded and the lightest "extra long" springs were rated to 1200kg.

I have seen first hand what too hard a spring does to the contents of an off-road trailer so I wanted the springs to match the weight as best as possible.
This is the spring I have bought: http://www.industrialsprings.com.au/ies1145.htm

Let me know what you think.

Thinking about it know I probably should have bought something like an XJ spring although I don't know what they are rated.

I could have just made the trailer heavier or carried more junk but I though that defeated the purpose of a light off-road trailer.:p

Will mounting the shocks on an angle towards the centre of the trailer cause a decrease in shock ability? I have seen a few shocks mounted like this ( I think Nissans are mounted like this) but wondered if I am just better doing it as straight as possible.

Which are the double acting shocks? I think the tough dog foam cell only damp in one direction. Is it the mono shocks that are double acting?

[Blknight.aus]

Im not sure on exactly how your going to do your springs but might I suggest that the rear springs off of a LWB series and the mount plate for them would do you nicely as they provide a well mounted shocky bolt and theyd be good for a shade over a tonne a pair total and if you want em lighter just start pulling the smaller leaves out. If you can find an old wreck you can get away with it cheap.

On that note. If you want the Front spring mount plates Im pulling whats left of the frontof bug 2.0 apart shortly and your welcome to them, the shocks and the springs if its any good to ya.

[walker]

Thanks, but like I said, I have already bought the springs, they are about to be welded on tomorrow.

On another note, I picked up the axle and springs and hitch on Monday finally. Got it home from Dandenong and went ot test it all out only to find they had installed a D1 stud pattern not D2. :mad: :mad: :mad:

Unfortunately they can't just change the hubs over, they have to do a whole new axle, something to do with the small PCD on the D2.:(
So they will have the new one ready Friday and I just have to go back and pick it up and give the other one back.

[Buggerluggs]

Adam,

If you look at an older Falcon station wagon the shocks are mounted inside the springs and angled toward the car centre. The lower point is mounted under the spring as far out board as possible. This is because of the packge constraint to keep the load floor as low as possible. This might be a solution for you and you could use off the shelf Ford type shockers. All the work will have been done for you, especially if you copy the geometry.

[Buggerluggs]

Adam,

Had a quick look at the springs you are getting. They have a military wrap according to the picture. This is a very good feature for an off road spring. the military wrap is where the second leaf wraps around both eyes at the ends of the first leaf. This is because one of the highest failure points on the spring is the eye and with the military wrap the second leaf allows you to at leat limp home (over many thousands of k, but a little slower).

Looks a good design, I'm not sure about the stress levels but they would have followed basic design principles and you should be ok. The one this I am unsure of is the amount of travel the spring is designed for. If you go over their recommendations this is where you will over stress the spring and cause failure. You probably want to talk to someone about the desing condition for the spring e.g. how much Jounce and rebound is allowed for in the design.

Just finished looking at the site you directed us to. They have a better spring for what you really need. It's the IES1210. It is longer by about 65mm which will make a huge difference to the wheel travel.

[walker]

Yes, I know, the 1210 might have been better but it's too late. I think the biggest problem was the weight. When I spoke to them they said that using the 1210 with only 600kg on them would just cause everything inside to be shaken to bits on the corrugations.

They recommended the one I have because while you lose some articulation, it should give a softer ride and for outback touring work this was what I needed.
If I take it up the hills then it will be slow work and I will just have to drag it over anything.:D


As for shocks, are they less likely to fade on leaf springs because they are not having to travel as far? I was going to use a good off-road shock but if it is not going to fade on the corrugations then I could use a cheaper one like a monroe or pedder.

[Buggerluggs]

Yes I agree that at a light load they will not flex enough and just bounce. A shock gets hot based upon the rate and frequency of ocillations. It does not matter who makes it, the issue is which one will handle the degree of heat build up better. Leaf springs by their very nature of steel leaves rubbing against each other have a degree of shock absorption built in, but don't count on it. I guess the best way of looking at it is to build the unit to the point that you can load/unload the suspension and see just how far it will move. Then translate that into what will happen with the shockers. If they move through say 8" of travel, similar to the Disco, then the amount of heat build up will be similar. If on the other hand you find because of angles etc it only travels about 4" then you could probably get away with a cheaper one.

[walker]

8" of travel!!!!!!!

I would have thought with leaf springs you might get 2" travel.

[Buggerluggs]

Thats why I talked about the Falcon wagon or ute springs. They were designed for 12" travel, and these are what I would put on mine!

I'm still trying to decide if I want to build a camper based upon the Sankey design concept. I would like to but is it just another hobby toy for me? Barbara does not always approve!

[walker]

Yes, well I still might end up going for another spring in the end. I want to build this up and then test it and give the spring company the benifit of the doubt since they recommended this spring.

But, I welded on the springs yesterday arvo and then mounted them on the axle and the springs seem very very very hard to me. Again, they are meant to be rated to 750kg (375kg/side) but with just the chassis built I tried pushing down with all my weight (and I have a lot of that) and I could not budge the spring even the slightest.


I am not sure of the technical aspects of leaf springs. How do you have a leaf spring that will carry the weight yet still be supple? With a coil, you make it soft but long then when it is installed it compresses but still is soft.

I am thinking you want a leaf spring that can flex a lot without hurting it (ie cracking or getting weak spots) and has a fair bit of curve in it so it sits high before it is loaded up then squashes down when loaded but still has plenty of room to flex more. This sound reasonable?

When they rate a spring at 375kg like the one I have does this mean it will not deform at all until it is loaded with 375kg???
When the spring is fully loaded will it be "more supple" than it is now?


I should have gone coils....at least I understand them!

[walker]

Truthfully I don't really care about articulation. At slow speeds you can drag a trailer over anything.
What I do care about is for the suspension to work at high speeds on the corrugations. So it only has to move a couple of inches but it has to do it easily and hundreds of times a minute. :o I will have to find some rough corrugated roads around Melbourne somewhere to test it out when finished.

[Quiggers]

I put shocks on my new box trailer (8x5 ft) a while back to stop it hopping around. the're near vertical, short and fat... and came from a wrecker; he said ex Mazda (the little truck with the 12" dual rear wheels) cost not much and seems to be better for the trailer (and the load of bikes), as in its not shaking itelf to pieces or the cargo, unlike the previous trailer. The shocks are doing their job, keeping the load under control, remember, they're not springs.....

I once towed a caravan round Aussie which shook itself to bits over 12,000 miles, but if the axle had been tied down like a decent suspension system in a car, the damage to the van would have been minimal, my opinion, but the physics (harmonics?) do add up....

GQ

[Pedro_The_Swift]

I would imagine with so many leaves the majority of suspension comes from the tyre sidewalls.

[Buggerluggs]

I can assure you that as an engineer working at Ford I designed leaf springs for the Falcon wagon that had 12" theoretical travel. In real life they had well in excess of 11". I also worked for the company that made the very same springs and we tested them on a hydraulic road simulator with 12" travel. Believe me they work!

I would put such a spring onto a trailer with travel limited to about 10-11" limited by the bump stop and shocker extension.

If you want to go another way then you can replace the front half of the leaf spring with a rigid tube bolted to the axle and swinging from the front eye, but using either a coil spring or air bags. This will give you a similar ride situation.

If you are really concerned about corrugations then go independant. Same as above but instead of a single tube axle make two swing arms from the side. You will end up with a longitudinal radial arm and a cross radial arm giving a swing curve which changes the steering characteristic on role. This is what TVan have done, but with coils.

How sophisticated do you want to get? I still hang my hat on the long leaf springs for low cost and reasonable performance.

[incisor]

http://www.vehiclecomponents.com.au/gallery/Cruisemaster/Cruisemaster%20LT%20Display%20Stand%201.JPG

this is what is under my camper trailer.....

pretty dam fine bit of gear IMHO

[Xtreme]

As leaf springs need to slide against each other, try greasing between the leaves. I did this after I fitted a brand new set of rear leaves under my Series 3 LWB about 30 years ago. When first fitted, I jumped on the towbar and got absolutely nil movement, then I greased between the leaves and tried the same 'jump' test and the difference was amazing - about two inches of supple movement!

In order to get the grease between the leaves, I had a 150mm long, chisel shaped tool with 3mm hole drilled about 100mm up the middle connecting to a grease nipple screwed into the side. I simply took the weight off the springs, drove the tool between the leaves, inserted the grease using a grease gun and while the tool was still separating the leaves, I spread the grease around using a hacksaw blade.
Do this every 10 or 20 thousand K's or before a major trip and all will be sweet.

I currently have a camper based on a 130 tub with greased LWB Series 3 springs and shocks and it rides superbly whether loaded or empty.

Roger