Building an 80 series trailer

Joined
Sep 30, 2014
Messages
573
Hey guys,

Looking for some advice regarding custom building a camper trailer potentially using 80 series suspension/design/parts.
Just FYI these these are the requirements/aim or the trailer:

1. Internal flushing toilet/bathroom.
2. Internal shower with onboard hot water burner (probably using propane/LPG)
3. Stove/burner hooked up to propane/LPG tank.
4. Ability to carry decent amount of firewood
5. Ability to carry a decent amount of water (even a short distance), maybe 200-400 litres.
6. Good ground clearance/ability to go down 4WD tracks.

So basically when going on camping trips with the misses she wants the ability to have a shower and have a proper toilet with no spiders/snakes (which is a real problem here in Aus). Now normally i would look to camp near a river for water supply, but would like the ability to pump on a bunch of water when near a stream to carry to a dedicate campsite. Likewise the ability to carry enough firewood for a night or two. So weights could vary from say 1000kg to 2500kg+ fully loaded for short periods.

So I will be custom building the entire trailer from scratch. It will be using a proper offroad hitch, electric trailer brakes with break away stop function. Where i need help is with the design of the suspension/axle. These are the 4 options I am considering...

Solid Axle Version
So the following 3 options would be using this solid axle:

Axle.png


(I did consider using an actual 80 series axle which would make life easier, but means a bit less ground clearance, a bunch of work to fit the electric trailer brakes and potentially a bit harder to get registered/approved. Even though this axle isn't exactly cheap, its a certified solution and they will fabricate it to match my 80 series track width which saves me a bunch of time).



1. Basic leaf spring design (the same as pretty much any other trailer) with added shocks.
Advantages is its relatively cheap and very reliable, very high carrying capacity (3000kg). Fairly light weight relatively speaking
Disadvantage is the springs would be setup for one specific weight, not easily adjustable. Very bouncy ride

2. Build a triangulated 4 link setup using the axle above utilising standard 80 series rear upper/lower control arms (I have a set of standard ones left over from a build, so no additional cost). Couple this with airbag suspension and decent shocks.
Advantages is its relatively cheap, should be pretty reliable, very high carrying capacity, airbags can be adjusted for varying weights.
Disadvantage is ride quality will be average, may have less clearance from the upper control arms to the trailer floor? Could be reasonably heavy

3. Build a 3 link setup utilising 80 series front control arms (but flipped around so they mount over the top of the axle with the "chassis" end at the front of the trailer. Use airbags with shocks.
Advantages is its relatively cheap and should be pretty reliable, very high carrying capacity, airbags can be adjusted for varying weights, should also have better clearance than a triangulated 4 link.
Disadvantage is the ride quality will be average? Probably the heaviest solution.

4. Purchase a heavy duty independent suspension setup like this one below:
IRS.png


Advantages is it'll give the best ride quality (maybe?), Is less fabrication work for me, can adjust the airbags to suit weight, proven design, better ground clearance (maybe?)
Disadvantage is cost (I could probably build the other setups for around $1500aud, this one is $3600...), load carrying capacity is slightly less but still probably more than enough. The shock angle in this design isn't ideal...

5. Purchase a medium duty independent suspension setup like this one below:
IFS Medium.png


Advantages is it'll give good ride quality, less fabrication work for me, proven design and better ground clearance. Cheaper than the heavy duty option above.
Disadvantage is the springs cant be adjusted for changing weight. Load capacity is low, shock angel isn't great, still fairly expensive ($2200aud)

So i am open to ideas/suggestions. I am a pretty good fabricator and like the idea of building a 3link/4link setup just for the experience. That said, I don't want to go to the effort of building something that doesn't work or needs modifications.

Cheers,
 
Last edited:

Road Apple

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There are a few threads in the Trailer forum. A quick search found trailers with stock axles, but no linked trailers. I also look forward to your build.

 
Joined
Sep 30, 2014
Messages
573
Thanks guys, I'll spend some more time searching through the trailer tech forum but didn't find a lot of relevant info initially.

This build will take a while, I'm still finishing off the 80 series. Just wanting to start designing so I can get a list of required parts. Occasionally ebay do a special for Huntsman products meaning i could get 15-20% off their axles (and they are only a 20 minute drive from me). Just want to have a design locked in so i can jump on any specials if/when they are offered.

I am leaning towards using flipped radius arms with the solid axle. I figure if i can get the axle for $800ish (on special) then I have the majority of the rest of the parts meaning the prices stay relatively low.

I did look at buying a camper trailer, but haven't found anything designed around a flushing toilet or shower. I already have a 4 person roof top tent and the back of the cruiser kitted out with fridges etc, so really can't justify the price of a camper that doesn't meet the requirements. I am a bit concerned with weight, but would prefer to overbuild the trailer and not have to ever worry about breaking it than under-building it an having issues (hence going for 12" brakes and 3000kg rated axle even though it may never see more than 1500kg. My HDJ80 is a 1997 build with 3500kg towing and already has an electric brake controller so makes sense to build the trailer to match).

There are 12v Macerating toilets design for caravans which can automatically pump to an onboard septic tank, and can auto pump/empty out at the end of a trip. I figure going to this effort means the miss's will be far more keen to come along, meaning i can spend more time/money kitting the cruiser out properly.
 
Joined
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Messages
9,026
Honestly my offroad pop up camper checks just about all your requirements. It has indoor and outdoor shower, flushable toilet, 6 lug axles, leaf springs, a front deck that I put all kinds of stuff, electric brakes, electric winch for the roof, 35gallon fresh water tank, 6 gallon hot water tank, dual propane tanks, propane heat, propane stove, enough sleeping space for 4 adults and 2 dwarfs. I just added solar, a second battery, a 12v/110v/propane fridge, a wireless roof winch control,, and air conditioning. Here is a older pic. It's not fully opened up here but you get the idea. Look up offroad pop up campers. You can get a older one like mine for less than 10k us dollars. If I shortened the front deck and lifted the suspension a bit more I could really go some crazy places with it. But I think i will stop for now.
20210508_205723.jpg
 
Joined
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Location
CA
I've always wanted to do a 80 trailer.

This is my 3rg gen Toy pickup trailer built off a 2wd frame. I ditched the axle and put a 4wd axle for 6lug and did a ubolt flip kit for an instant lift with stock 4wd leafs. Threw my spare 35 on cruiser wheels and welded on a pintel hitch. Got a used ARE commerical she'll and changed out the windows to RV screened tinted windows.

Both sides open up. One for access to bed. The other side to a shelf I use for storage and sooner or later a kitchen setup.

Just finished wiring a 105 amp AGM battery and full lights and 12v and solar hookup.

For cost and versatility I would go a toy pickup. Plus they are just easier to build.

But I've always wanted a matching 80 trailer. Will be watching your thread for ideas 😀

IMG_20210807_211902.jpg
 
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Across the pond, and upside down
200-400 litres of water sounds excessive. Cutting that would reduce overall weight a lot.
Reducing the missus's expectations would as well :rofl:
5-10 litres is enough for a decent shower of your expectations aren't to have flowing water the whole time while you suds up. Quick wet down, suds up, quick wash off!
I'm a big dude and can have a decent wash with 5 litres without any trouble.

My folks travelled all over remote northern Australia with 70 litres of water for cooking and washing, and 20 litres back up drinking water. They used 2 litres each daily.

A lot of commercially built independent offroad trailer suspension systems don't look particular impressive to my mind. They seem to be extremely bulky which cuts into any ground clearance gains.
 

Broski

I love Wheelin my 80
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Hey guys,

Looking for some advice regarding custom building a camper trailer potentially using 80 series suspension/design/parts.
Just FYI these these are the requirements/aim or the trailer:

1. Internal flushing toilet/bathroom.
2. Internal shower with onboard hot water burner (probably using propane/LPG)
3. Stove/burner hooked up to propane/LPG tank.
4. Ability to carry decent amount of firewood
5. Ability to carry a decent amount of water (even a short distance), maybe 200-400 litres.
6. Good ground clearance/ability to go down 4WD tracks.

So basically when going on camping trips with the misses she wants the ability to have a shower and have a proper toilet with no spiders/snakes (which is a real problem here in Aus). Now normally i would look to camp near a river for water supply, but would like the ability to pump on a bunch of water when near a stream to carry to a dedicate campsite. Likewise the ability to carry enough firewood for a night or two. So weights could vary from say 1000kg to 2500kg+ fully loaded for short periods.

So I will be custom building the entire trailer from scratch. It will be using a proper offroad hitch, electric trailer brakes with break away stop function. Where i need help is with the design of the suspension/axle. These are the 4 options I am considering...

Solid Axle Version
So the following 3 options would be using this solid axle:

View attachment 2754783

(I did consider using an actual 80 series axle which would make life easier, but means a bit less ground clearance, a bunch of work to fit the electric trailer brakes and potentially a bit harder to get registered/approved. Even though this axle isn't exactly cheap, its a certified solution and they will fabricate it to match my 80 series track width which saves me a bunch of time).



1. Basic leaf spring design (the same as pretty much any other trailer) with added shocks.
Advantages is its relatively cheap and very reliable, very high carrying capacity (3000kg). Fairly light weight relatively speaking
Disadvantage is the springs would be setup for one specific weight, not easily adjustable. Very bouncy ride

2. Build a triangulated 4 link setup using the axle above utilising standard 80 series rear upper/lower control arms (I have a set of standard ones left over from a build, so no additional cost). Couple this with airbag suspension and decent shocks.
Advantages is its relatively cheap, should be pretty reliable, very high carrying capacity, airbags can be adjusted for varying weights.
Disadvantage is ride quality will be average, may have less clearance from the upper control arms to the trailer floor? Could be reasonably heavy

3. Build a 3 link setup utilising 80 series front control arms (but flipped around so they mount over the top of the axle with the "chassis" end at the front of the trailer. Use airbags with shocks.
Advantages is its relatively cheap and should be pretty reliable, very high carrying capacity, airbags can be adjusted for varying weights, should also have better clearance than a triangulated 4 link.
Disadvantage is the ride quality will be average? Probably the heaviest solution.

4. Purchase a heavy duty independent suspension setup like this one below:
View attachment 2754791

Advantages is it'll give the best ride quality (maybe?), Is less fabrication work for me, can adjust the airbags to suit weight, proven design, better ground clearance (maybe?)
Disadvantage is cost (I could probably build the other setups for around $1500aud, this one is $3600...), load carrying capacity is slightly less but still probably more than enough. The shock angle in this design isn't ideal...

5. Purchase a medium duty independent suspension setup like this one below:
View attachment 2754794

Advantages is it'll give good ride quality, less fabrication work for me, proven design and better ground clearance. Cheaper than the heavy duty option above.
Disadvantage is the springs cant be adjusted for changing weight. Load capacity is low, shock angel isn't great, still fairly expensive ($2200aud)

So i am open to ideas/suggestions. I am a pretty good fabricator and like the idea of building a 3link/4link setup just for the experience. That said, I don't want to go to the effort of building something that doesn't work or needs modifications.

Cheers,
#5 looks to be the best set up ;) 🤷‍♂️
 
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Silvan, Austraila
I wouldn't get sucked into any type of exotic suspension on a trailer. 2 points of wheel contact on the ground there absolutely no need side to side articulation. I'm yet to see a trailer stay level (side to side) over wombat holes. The hitch does all the articulation. Basic leaf has done the job for decades for me.
 

smritte

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I wouldn't get sucked into any type of exotic suspension on a trailer. 2 points of wheel contact on the ground there absolutely no need side to side articulation. I'm yet to see a trailer stay level (side to side) over wombat holes. The hitch does all the articulation. Basic leaf has done the job for decades for me.
This.^^^^^^^^^^
I've built several off-road trailers over the years. All of the capable of navigating moderate to extreme trails. Personally, I don't like the shock angle of that independent suspension you had a picture of. As the trailing arm goes up the shock flattens out and becomes useless. It looks like they wanted an Iron Man shock as a selling point but couldn't get one short enough to function. All of my trailers use solid axle with long leaf springs and good gas shocks from an early VW. Leaf springs and shocks are more than enough. If your really needing the clearance for large rocks then go to the independent. The issue with rocks is, you need to make sure the trailer follows your line exactly and if its going over a rock at the same time as your tow rig is pulling up on a rock or your tow rig is in sand while the trailer is pulling up on a rock, traction gets tricky. The heavier the trailer, the worse this is.


Here is my teardrop on some moderate rocks. I don't have anything quick with my M-100 in bigger rocks. The suspension on my teardrop is solid with long leafs and 8 inch of travel. The spring rate makes it flex more than most of the independents. You can see how much it still leans.


Mengo Pass.jpg



Mengo 2a.jpg
 

smritte

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All the high end trailers and late model military trailers use independent suspension for a reason.

OK.
Im sure your opinion is based on testing and watching diffrent kinds of suspensions on trailers like I have. I have played with solid axles with and with out shocks. Followed several timbren axled trailers and a few very well built custom independents in most terrains from hard core rocks to sand to fast dirt road. I can design and build any suspension. I choose and I choose solid for its simplicity and the fact there is very little difference on a trailer.

These are not trophy trucks or high end track cars. The only difference here is unsprung weight and center ground clearance. One could argue that Trophy Trucks and Indy cars run independent suspension but why are we not converting our Cruisers? If someone wants a good independent trailing arm suspension, they should run a coil spring not a rubber spring like one of the bigger companies push. Why? Because now you can set the spring rate properly.
Most "Off-Road" trailers are designed as street trailers with dirt tires and a lift. The spring rate is designed for carrying weight not axle flex. A 3500# axle is coupled with 2 3500# springs. I run a 3500# axle with 2 750# springs for proper support and flex.
 

Broski

I love Wheelin my 80
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OK.
Im sure your opinion is based on testing and watching diffrent kinds of suspensions on trailers like I have. I have played with solid axles with and with out shocks. Followed several timbren axled trailers and a few very well built custom independents in most terrains from hard core rocks to sand to fast dirt road. I can design and build any suspension. I choose and I choose solid for its simplicity and the fact there is very little difference on a trailer.

These are not trophy trucks or high end track cars. The only difference here is unsprung weight and center ground clearance. One could argue that Trophy Trucks and Indy cars run independent suspension but why are we not converting our Cruisers? If someone wants a good independent trailing arm suspension, they should run a coil spring not a rubber spring like one of the bigger companies push. Why? Because now you can set the spring rate properly.
Most "Off-Road" trailers are designed as street trailers with dirt tires and a lift. The spring rate is designed for carrying weight not axle flex. A 3500# axle is coupled with 2 3500# springs. I run a 3500# axle with 2 750# springs for proper support and flex.
Not trying to argue with you, and I did not quote your post. Just stating facts.
What works well for some might not work well for others ;) 🤷‍♂️
 
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smritte

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Not trying to argue with you, and I did not quote your post. Just stating facts.
Sorry if I came off wrong. Off-Road trailer suspension is a conversation I have fairly regularly. People get caught up in what the latest trends are or what the military does. Both systems have their plus and minus. Personally, the minus on independents are many with what the military runs as well as some of the "bolt in" systems.
 

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