Making a big trailer more off-road worthy?!?

[dustboy]

Hi folks-
I just finished building this 6x12 cargo trailer conversion. It's got a full-size bed, running water with 21-gal tank, 12v electric system, all of which is removable by forklift so I can use it on Monday to deliver cabinets.



It's not really built for overlanding, but I do need some help making it travel better off of paved roads. We tried to get out to Bowman Lake over a rocky fire road (along with minivans and 2WD cars), and had to stop halfway because the trailer was taking such a beating.

We aren't asking this trailer to take on the Rubicon, but it would be nice to be able to explore a bit more off of the smooth roads.

Specs:
-Tandem 3,500 lb. axles, sprung-under. GVWR is 7,000 lbs
-leaf springs
-standard ST205/75D15 bias-ply trailer tires (@ 40 PSI)
-Estimated 3,000 lbs. fully loaded

Here are a few things that crossed my mind:
-Remove a leaf from each pack, or downgrade the leaf packs to make the suspension more supple. The full weight rating is not needed.
-Add shocks

What do you think?

Here's the build thread on TNTTT if you're interested.

 

[John E Davies]

The first step is to convert the springs to sprung over - that gains you much needed clearance and departure angle. You will have to change your ball mount to level the trailer. Guys with lifted 4wd trucks routinely do this to their trailers.

Add greaseable shackle bolts and keep them well lubed.

Add hydraulic shocks.

If you axles are Dexter - they have kits for the last two steps, but the shocks won't work if you switch the spring mounts. You may have to look for a set of universal shocks.. A welding or hitch shop can help with fabricating mounts if you can't weld (safely).

I don't think you need to mess with different tires yet - see how it does with the extra clearance and shocks.

It's probably unlikely that you could get a tandem trailer that big into a situation where you would need an offroad coupler, but maybe..... I dragged a 26 ft Nash travel trailer into some pretty rough situations (getting from forest road to campsite), but I never got to where I risked popping a hitch ball.

You do need to fully understand how much stress this sort of towing puts on the frame and cabin structure. Go slow and be very paranoid.

John Davies
Spokane WA USA

 

[skersfan]

Tandem for any serious off roading is going to be questionable. Can put a lot of torque on the side walls of the tires. You are weigh over sprung as you already know. you need to find out how much it will drop by removing one leaf spring. It needs to be sprung at the maximum weight. Very doubtful you will see 3000 while off roading. Meaning it will get beaten apart.

I assume you build cabinets, as that is a nice looking unit you have in the trailer.

In the long run, it might be cheaper and less repairs if you went with a single axle closer to the weight you are wanting to run. I would guess the trailer weighs under 2000 or right at that. You might just remove one axle and leave the 3500 pound and remove a leaf. Design something in the extra wheel well space.

Bob

 

[gotink]

First lower you air pressure in the tires ...the cheapest and simplest way to start ...think 20# and go down from there...my military trailer I run a 15psi to 10psi on and off road fully loaded....play with things abit ...it will help out more then you can imagine...

 

[Cabrito]

Nice work there Evan.

 

[loren85022]

Payload is also a factor. Albeit not so much with tandem. But if the cooler is loaded, and you're hitting washboards, it's going to increase the springs reaction. Keep it tounge heavy.

 

[uscg2008]

You need to start a build thread on here. I've been scoping out your build on tntt for a while. There are a couple other guys on here with cargo conversions. Ill be starting a build soon too.

 

[dustboy]

Thanks all for the replies.

I'm definitely not converting to sprung-over. Ground clearance is not the issue, it's already got more clearance than my tow vehicle (Honda Ridgeline) and I don't want the floor any higher. We are really just doing bumpy forest roads, not jeep trails.

I can weld on some shock mounts, John Davies do you know where to get such a kit?

I guess I could drop an axle, question is, which one? The tandem setup is nice for 95% of the use that this trailer sees, I don't have to be quite as careful about load balancing and it tows very nicely on the highway.

 

[skersfan]

If I were dropping one it would be the front. It will be a bit more tongue heavy, but you are removing a lot of the weight. Shocks are a good idea for sure, check with Red Neck trailer supply, or take a look at Jeff Wanamog's or Cowboy's builds, they have modified the Cargo trailers and done excellent jobs on them.

The thing you really need to remember and know is that currently you are so way over sprung, that has to change. Off roading being 4000 over sprung will destroy the trailer, no ifs and or butts. Air pressure makes a difference if you are in the ball park. I run my off road trailers with 25 on the road and as low as 10=12 off road, could go less for sure.

The problem with trailers, and ever developing confidence in one, is we can get on to a trail, over the trailers capabilities. Lowering air pressure on a tandem can cause some problems on tight turns, as the wheels/tires normally on this type of trailer were designed to have 80-90 pounds of pressure in them. Not much side wall movement. Will be easy to pop one off. Fire roads you should be fine though.

Bob

 

[rockwood]

We need to see this pulled out!

 

[lqdchkn]

***OFF TOPIC***

So how were the conditions up there? I've been wanting to get up to Linsdsey lakes which is right near by.

 

[dustboy]

lqdchkn, we camped on Bowman Lake Road, and found a gorgeous spot near Canyon Creek. Unfortunately we never saw the lake! We were creeping so slow on the way in that the transmission overheated, and I was afraid to climb up over the big hill to Bowman Lake. Oh, and we were down to 1/4 tank of fuel, so dropping the trailer for a day trip was also risky.

Air pressure makes a difference if you are in the ball park. I run my off road trailers with 25 on the road and as low as 10=12 off road, could go less for sure. Lowering air pressure on a tandem can cause some problems on tight turns, as the wheels/tires normally on this type of trailer were designed to have 80-90 pounds of pressure in them. Not much side wall movement. Will be easy to pop one off. Fire roads you should be fine though.

Bob

These tires want 50 PSI, and they are cheap bias-ply. I would definitely be afraid to run anything less than 30 or so. They are due to be replaced, so I might upgrade to LT radials, in which case I could run 20 PSI no problem. Aw shucks, guess that means I'll have to add OBA too.

You can see the leaf packs are 4 leaves thick. Which leaves, and how many do you think I should pull?


Here's a bit more of the galley under construction.



From the front door, view of the bed and storage underneath.

 

[skersfan]

In honesty, I have no idea. I have not used that type of axle in over 25 years. Try to find out who the manufacturer is, most likely Dexter. They can tell you is my guess. But there are guys on here that know that stuff. Some one will help I am sure.

Nice looking cabinets. I am looking to make some out of aluminum on my next personal trailer. I like the fork lift idea, I had thought of that when I started mine, all being exactly the same. Did not work out that way darn it.

Bob

 

[lqdchkn]

lqdchkn, we camped on Bowman Lake Road, and found a gorgeous spot near Canyon Creek. Unfortunately we never saw the lake! We were creeping so slow on the way in that the transmission overheated, and I was afraid to climb up over the big hill to Bowman Lake. Oh, and we were down to 1/4 tank of fuel, so dropping the trailer for a day trip was also risky.
View attachment 166544

Thanks for the info, I'll definitely adjust my priorities accordingly

As for the transmission woes, that sucks but (and let me apologize in advance) ya know what what? I have to say it; Honda ≠ Truck

 

[rockwood]

Ridgeline is pretty decent but by the sounds of it, a larger tranny cooler ie aftermarket should be on your list of modifications. Or at least add one in line with the current set up. Think Ridgelines are spec'd to over 5klbs on road. What does the trailer weigh and how much stuff was in the Ridgeline
BTW, I have a Pilot with 160k that I've used to tow all kinds of trailers.