: Off road trailer Suspension Tech


Maytag
09-16-2008, 08:10 PM
So after looking around at all the trailers for a bit, and seeing a few different styles of suspension...what is everyones preference for all around capability?


I know the suspension is not as crucial as on the tow rig, but is flex as important? soft or firm ride? solid axle or independant suspension? A sway bar with the independant suspension?



I know for me I'd like one that will follow easily on the rocks and not beat up everything inside

Java
09-17-2008, 05:38 AM
ive seen that most people run leaves, but the chaser trailors AT makes use indepedntant with air bags. i think what i have seen that helps the most is shocks, they often get left off of trailors.

wheelerfreak
09-17-2008, 08:49 AM
I run leaves on mine, in fact they are the same leaf springs as the tow rig. I also run shocks on mine just to reduce the pogo effect. I built my trailer around the 88 Toyota V6 p/u rear axle housing. It uses the same leaves, axle, shackles, plates etc as the tow vehicle. This allows me to always have spares available for the truck if needed as well as the same wheels and tires if I need another spare. If needed I can swap the whole housing into my truck if I really f it up since I have the same gears and a lunch box locker in the trailer axle (it came that way when I bought it, I didn't add the locker). I was looking at interchangability for the use this truck/trailer gets out in the boonies. IMO leaves are easier to fix or rig than just about any other suspension, and are durable too.

Again, IMO, match your trailer axle and suspension to your tow rig.

The Adam Blaster
09-17-2008, 11:22 AM
Wheelerfreak it sounds like you've got a pretty good setup going. ;)

I think the issue with having shocks on a trailer is the space requirements. Under the body of the trailer there just isn't enough space unless you have a really tall trailer. On the sides of the body would work, but you'd probably have to mount the shocks inside the wheel wells -- possibility of damage from rocks getting picked up etc.

The alternative might be to stick with leaves and add some of those "helper shocks" that are advertised and get mounted along the length of the spring pack.
I've heard they do in fact help with excess bouncing in a pickup, so why not in a trailer?

wheelerfreak
09-17-2008, 03:09 PM
I gotta say one of the biggest reasons I went to a relativley soft suspension and shocks was my beer:D I was sick of getting to a camp site and all my bottles were broken or popped open due to the rough ass riding typical trailer suspensions. Or you would pop one open and it would foam up mmmmm:beer: So I guess I'm an alcoholic since that was my motivation:laughing:

The Adam Blaster
09-17-2008, 04:53 PM
Beer is one of the greatest motivators in the world. :D

There's other equipment i wouldn't want to get beat up too badly also... I'm thinking about my camp stove, and my lantern specifically. It would suck to roll up to camp, unload the gear and start making dinner only to find out one of the lines in the stove was damaged... :(

deepmud
10-29-2008, 02:19 PM
Lone Wolf Expedition (http://www.lonewolftransglobal.com/LoneWolf.htm) (good read btw) brought a tough, leaf sprung trailer. He spent a lot of time and effort repairing it multiple times.

I thought:

A: Geez, get an on-board welder! more than once he needed one bad.

B: An independent trailing arm axle might have stopped all his troubles before they started.

I realize leaf springs are tough, but they don't absorb rough roads so smoothly - they tend to take a hit from a pothole with a violent transmission of force, rather than a smooth action of the suspension. A swing axle tends to swing back from the bump as it goes up, helping the hit get spread out more smoothly. I've searched a bunch, the Aussie's seem to use a lot of trailing arm suspensions under their campers - and they have a lot of rough roads in the Outback.

Plus my own experience with a swing axle trailer has been trouble free, and I've abused mine with loads of logs towed over downed trees, down rough trails and usually way overloaded. I then took the same trailer, widened the deck, added a box for camping/cooking, and took it to Washing D.C. and back - from Anchorage, Alaska - about 15 thousand miles in one trip. The tow rig was an AWD Aerostar - not a real expedition rig, but it served to carry the family of 5 and averaged 17.5mpg overall. Off road getting firewood I have hauled it loaded over downed trees and thru deep water crossings. It's never needed anything other than a couple of bearing services, which was easy with a standard spindle/cone bearing arrangement.

I know it sounds weird to say "go to the junkyard and get an old small car suspension" but it worked great for me so I thought I'd offer up the idea.

pics.
http://www.supermotors.net/getfile/679616/fullsize/trailer001.jpg

Here you can see the swing arm suspension - it's got built-in torsion springs - easy as pie to bolt to a frame of your choosing.
http://www.supermotors.net/getfile/679618/fullsize/trailer003.jpg

the camper box. I can put stuff in it, cook from it ( the side door flops down and makes a shelf) and it's strong enough for a 300 pound man to walk on.
Obviously, it's removable so I can use it as a flat-bed stuff-hauler.
http://www.supermotors.net/getfile/679624/fullsize/trailer007.jpg

2300 pound pallet - too much for the Suby, it's almost bottomed out - I off-loaded about 5-600 pounds to the tow rig before hitting the highway at 65mph. So this is a LIGHT DUTY trailer, like less than 1500 gross for long distance travel. Luckily, it's a LIGHT TRAILER - I can pick it up easy, I'd guess it's less than 350 pounds as a flatbed. That leaves a lot of capacity for carrying tents,fuel,water, etc.

http://www.supermotors.net/getfile/683651/fullsize/trailer-loaded.jpg

Off-road - it's got GREAT clearance. Also Subaru is a 4 on 5.5 circle, you can easily do a 6 on 5.5 conversion or a 5 on 5.5 conversion with care. My plan is to swap to toyota rims to match my Zuk's new axles.

http://www.supermotors.net/getfile/207590/fullsize/p1010011.jpg


I'm sure it would keep your beer safe too. It's very smooth riding :D

Berne
10-30-2008, 10:35 AM
I know the suspension is not as crucial as on the tow rig, but is flex as important? soft or firm ride? solid axle or independant suspension? A sway bar with the independant suspension?



I know for me I'd like one that will follow easily on the rocks and not beat up everything inside


I think "flex" really has nothing to do w/ the trailer. w/o 2 axles, there aren't any opposing forces, so the only "flex" the trailer will have in its suspension is just from the slight COG changes when it leans over. All the "flex" will be between the towrig and trailer through the hitch.

I'd say the suspension on a trail-trailer should be as soft as reasonable to handle the weight.....again, mostly for taking away the harshness on the cargo ( :beer: )
thats all about spring rate.....fancy suspension design is probly somewhat wasted on a trail-trailer, the tires aren't powered or braked, so there won't be any weird dynamics......but if you go w/ some trailing arm setup, make sure the angles aren't such that it'll jack while backing up against an obstacle.

--B

maxyedor
10-30-2008, 09:56 PM
I'm starting on one fore a friend of mine that will use a Range Rover chassis and stock 3-link with coils, we figure it will have about the same weight on the axle as a loaded Range Rover would so everything will end up sitting and performing about the same as a full truck. It may end up a few hundred pounds lighter in which case we'll I'll take the medium duty Rovertym springs out and swap in some lighter duty 2" lift OMEs and add a spacer so it'll still sit level with the truck and flex about the same.

I'll post a build thread once we really get it started.

biere
12-12-2008, 02:49 AM
For those with really lightweight trailers, how much do you think the tire sidewall is your main suspension vs. the leaf springs or torsion bar or other type suspension used to support the axle?

I am looking to just swap a heavier duty axle under a lightweight aluminum utility trailer and go up to stock size jeep rims and rubber. In talking with some folks they said that until I load up the trailer with some decent weight I won't be using much of the suspension on the trailer.

b1gsleep
12-12-2008, 05:47 AM
For the people that are running the same suspension as their vehicles; do you limit the travel on the trailer to keep it from falling into everything on the road? How much flex is really necessary on a trailer with a dumb axle?

deepmud
12-12-2008, 02:00 PM
For those with really lightweight trailers, how much do you think the tire sidewall is your main suspension vs. the leaf springs or torsion bar or other type suspension used to support the axle?

I am looking to just swap a heavier duty axle under a lightweight aluminum utility trailer and go up to stock size jeep rims and rubber. In talking with some folks they said that until I load up the trailer with some decent weight I won't be using much of the suspension on the trailer.

what is "really lightweight"? Less than 500 ? 1000? No sidewalls other than ATV tires will flex or absorb much with really light loads. My Samurai on 35's had to run 18 psi on the highway just to get the tread to lay flat, and rode like a cement truck with my stiff leaf springs.

My Subaru trailer moves it's torsion suspension a lot on bumpy roads with only a few sheets of 3/4 plywood from Home Depot on it. I've been behind it while driving, torsion arms seem to react to very small bumps. Even completely unloaded it does not bounce. Even with it so soft, the only time I had trouble with sway on corners was when I had a 3 foot tall box built on the back, and stacked a couch up on top of that to take home - it swayed a bit on corners, but then I had no shocks on it then either.

I would guess unless you get a really soft leaf set-up you are right, not much spring flex, mostly bouncy 35" tires. This is maybe a reason not to use the leaf system if you can. Rubber torsion axles are not very expensive and plenty strong, imho. Even a 3500 pound torsion has a couple inches of initial take-up that would allow a light load to be suspended by something other than the tires.

johnwiseman
12-12-2008, 05:29 PM
I agree with the idea of using a car suspesion to even out the bumps. An expo trailer shouldn't be carring heavy loads anyways. Personally, i plan to use the left over bits from my blazers ifs to make my trailer. I think it will promote a lot of good handling stuff in my expo trailer as well as hande lot of abuse.

39ranger
05-14-2009, 08:52 PM
I have a little tent trailer that I want to convert from a solid torsion to a independent swing arm, using air bags (springs) and shocks.

I need assistance in designing the suspensions system. Here is what my original thoughts are. Swing arm pivots towards the front of the trailer and the axle welded to the other end of the swing arm and the bag in between.

The original axle was rated at 1500lbs so it is fairly light, however I have purchased axle/hubs rated at 3000lbs because I am going to add a little weight bigger tires and possibly carry a little boat on the top.

Thanks for your help.

existing set up.

http://i605.photobucket.com/albums/tt136/39ranger/Early%20Bronco%201970/tenttrailer2dims.jpg


Rough Idea of what I am thinking, just don't know how long to make the sing arms and where the best place to mount the air bag and shock

http://i605.photobucket.com/albums/tt136/39ranger/Early%20Bronco%201970/tenttrailerdims1.jpg

deepmud
05-16-2009, 10:04 PM
that looks like an AT Adventure Trailer style suspension - also used on lots of Australian off-road trailers. It's an excellent choice. If cost is a consideration, the Suby suspension might still be something you want to look at but AT has spent years of trial and error and come up with just about what you have drawn there.

p14175
05-18-2009, 04:33 PM
I have a VenturCraft pop-up tent trailer with torsion arm type suspension. There's no axle bar or housing to get hanged up on the rocks. I don't think I have ever loaded it to capacity (700 lbs), but the beer isn't shook up at the end of the trail. I think the tires are the primary suspension, but I am sure the trailer suspension is also softening up the bumps a bit as well. I am running 33x9.50 MTs on the trailer.

Unfortunately Venturcraft went out of business several years ago. They also made the trailer for towing behind touring motorcycles. I think it was called a Kwik Kamp. I recently spotted one (the motorcycle version) being towed behind a Samurai.

sheps
05-18-2009, 11:49 PM
this trailer has good on and off road manners plus is nice and soft
so you dont tend to brake stuff.
http://i415.photobucket.com/albums/pp234/supazukdarwin/002-28.jpg

http://i415.photobucket.com/albums/pp234/supazukdarwin/003-20.jpg

http://i415.photobucket.com/albums/pp234/supazukdarwin/001-37.jpg

deepmud
05-20-2009, 09:23 AM
I started to reply "Oh, that looks like an Australian style - they have gotten trailers to survive severe abuse down to a science" and then I noticed it IS in Australia :D I like the disc brakes too.

It looks like it would be easy to make your own from that style - maybe run some old TJ rear springs - they are a dime a dozen. That and and a 3k spindle and some square tube and you have instant homebuilt off-road trailer axle :D

Blue-Beard
05-22-2009, 10:48 AM
Dang deepmud, thats a cool idea of using a rear torsion suspension off a small passenger car from the junk yard! :smokin:

deepmud
05-22-2009, 01:18 PM
Dang deepmud, thats a cool idea of using a rear torsion suspension off a small passenger car from the junk yard! :smokin:

Thanks! Being broke is sometimes the mother of invention too :grinpimp:

jsawduste
05-25-2009, 09:04 AM
Used a set of XJ leaves swapped end for end to move the axle back. Turns out they were to soft. Added a main and a short to the pack and went SOA with a set of Monroe Gas shocks.

http://i303.photobucket.com/albums/nn156/jsawduste/P4220020.jpg

http://i303.photobucket.com/albums/nn156/jsawduste/P4090011.jpg

While this is still a project in the making. Thus far it has worked very well.

One of the keys (IMHO) is the tires. 37`s aired down to about 15 lbs. The sidewall takes up a lot of hit.

By the time it`s done it will have a complete RTT, water and electrics.

suprdave737
05-25-2009, 03:50 PM
Hey Sheps: Thats a beautiful trailer, thanks for sharing the pics.

sheps
05-25-2009, 05:05 PM
no worries mate. it is my 70y/o parents trailer. they can set it up in less
then 5 minutes. i will get some photos next time it is set up for you as it
is a brilliant set up, even has aircon:D

i am copying the suspension setup on a light weight tent trailer that i am
building to use behind my suzuki when i have a bit of progress i will post some pickies.

have a look at these, especially the t-van. they will follow a 4wd anywhere.
http://www.tracktrailer.com.au/

ChiScouter
05-25-2009, 05:08 PM
no worries mate. it is my 70y/o parents trailer. they can set it up in less
then 5 minutes. i will get some photos next time it is set up for you as it
is a brilliant set up, even has aircon:D

i am copying the suspension setup on a light weight tent trailer that i am
building to use behind my suzuki when i have a bit of progress i will post some pickies.

have a look at these, especially the t-van. they will follow a 4wd anywhere.
http://www.tracktrailer.com.au/

How do they actuate those rear discs?

jeeplt1
05-25-2009, 07:47 PM
jsawduste trailers lookin good. cant wait to see what ya do to it. keep us posted
curious what materials you built it out of. and dont say metal!

sheps
05-26-2009, 03:50 AM
How do they actuate those rear discs?

it is a basic over ride system, it works of the trailer coupling. every trailer over
750kg has some sort of braking system in Australia and the cable operated
disks is probably the easiest system to set up.

deepmud
05-26-2009, 03:29 PM
it is a basic over ride system, it works of the trailer coupling. every trailer over
750kg has some sort of braking system in Australia and the cable operated
disks is probably the easiest system to set up.

Surge brakes, we call 'em over here. Usually hydraulic - in fact I haven't seen any that aren't but I'm not a trailer expert :homer:
Cable would be simple. Does it take a lot of "travel" to actuate them? I assume they have a shock absorber on them to keep it from over-correcting? I will see if I can google my answers too, just curious :D

sheps
05-26-2009, 06:50 PM
Surge brakes, we call 'em over here. Usually hydraulic - in fact I haven't seen any that aren't but I'm not a trailer expert :homer:
Cable would be simple. Does it take a lot of "travel" to actuate them? I assume they have a shock absorber on them to keep it from over-correcting? I will see if I can google my answers too, just curious :D

same as the hydraulic set up but with cable. the cable systems have a lot less problems with the corrugated roads that we have in north Australia.

youngguns4x4
05-31-2009, 08:14 PM
Used a set of XJ leaves swapped end for end to move the axle back. Turns out they were to soft. Added a main and a short to the pack and went SOA with a set of Monroe Gas shocks.

http://i303.photobucket.com/albums/nn156/jsawduste/P4220020.jpg

http://i303.photobucket.com/albums/nn156/jsawduste/P4090011.jpg

While this is still a project in the making. Thus far it has worked very well.

One of the keys (IMHO) is the tires. 37`s aired down to about 15 lbs. The sidewall takes up a lot of hit.

By the time it`s done it will have a complete RTT, water and electrics.
I hope you were drunk when you cut your u bolts.

chrisevans2645
10-13-2009, 09:01 AM
i would say look for a surplus m101 trailer. they have 37" tires with humvee rims, standard 8 lug bolt pattern, shocks, and a high clearance axle. if you have a swiveling type pintle hook it can articulate until it rolls over. it also uses surge brakes. as for me i found a f350 cclb in the junkyard that already had the cab removed. i cut the tongue a little extra long so i can put a tool box and maybe a generator or whatever on it without taking up the bed space. for that i have no brakes yet but eventually i'll go with an electric over hydraulic setup. the brakes on the 101 trailers never have fluid in them either. i have seen brake fluid in the slightly larger humvee trailers and every time they would have a wheel lockup until you opened the bleed screw. the 101's are older so they probably got drained for the same reason. one thing i've considered doing if i ever win the lottery, put a hydraulic motor on my trailer going to the rear end. i would have quick connects going to the truck and if i ever get in a tight spot i could send power to the trailer axle. that another benefit of the trailer being similer to the truck is i can swap axles if i needed to.

deepmud
10-13-2009, 12:23 PM
Is weight even a consideration? The M101 weighs 700 lbs EMPTY. I don't want to haul 700 lbs dead weight - add just 300 pounds of load and you have half a ton bouncing around back there. My trailer will carry 500 pounds without any real stress, and total weight will be around 700 then.

chrisevans2645
10-14-2009, 11:54 AM
Is weight even a consideration?

no. lol i'm not too concerned about weight. my rig weighs 7600 completely empty then you add all my tools and stuff i always carry and it easily goes over 8000 then the extra stuff that i take when i go camping. i've never driven a light 4x4 and to me 700 pounds is light. plus i've filled a 101 trailer up to the roof with sandbags (full, well over the 3/4 ton rating) and the only thing that broke was the tire. i see what your saying but for me i don't care about wheight :tank:

skark_burmer
10-14-2009, 04:43 PM
I am thinking of picking up one of the M105 trailers, whats the difference between the 101 and 105?

Also the ones i am seeing are a very large 5 bolt pattern. Do i just buy a spare rim, or convert the hubs to something more useable?

chrisevans2645
10-15-2009, 01:15 AM
the 105's are for 7 tons. they have an air over hydraulic brake system and to sit level the pintle needs to be at least waist high. it's also heavier and has the split ring rims. the rims are offset like a dually, not sure if you could modify them or not. also i'm not sure what the weight capacity is. the 105 is a bit bigger than a 101 but not by too much. it's just a general purpose trailer for packs or trash etc.

asonico
11-14-2009, 07:12 PM
I like the concept.

Does anyone know a source of a kit? I'm just concerned about the alignment (camber, toe-in, tracking) adjustments.

I have a 900# tandem-axle fiberglass trailer (4000# gross capacity). The cab is 12 feet long and I've always wanted to make it a high ground-clearance off-road trailer. Currently it has those low rider Dexter torsion axles.

Art

deepmud
11-14-2009, 08:07 PM
like these right?

http://www.modmyrv.com/wp-content/gallery/mod-69-image-gallery/shock-absorbers-dexter-axles.jpg


Adventure Trailers does an upgrade, but I think they want to do it "in house".

asonico
11-14-2009, 09:44 PM
Deepmud, that a (Dexter Trosion axle), my trailer has two of those.

What I'm interested in as a kit is this:

deepmud
11-14-2009, 10:10 PM
www.adventuretrailers.com used to sell a kit.
http://www.jeepbrokers.com/product_reviews_adventure_trailers.htm
http://www.atreport.com/images/newsusplo.jpg

But I don't see it on their website - however, contact 'em, who knows?

asonico
11-16-2009, 11:15 AM
I called them, they don't sell kits, they only convert your trailers in-house. It should be easy to fab thse anyway.

The Adam Blaster
11-17-2009, 08:10 AM
What I'm interested in as a kit is this:

I'm really liking this design. It seems pretty simple, yet the components are fairly stout. Simple and beefy, sounds like a good combo for an offroad trailer. ;)