Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
12/1/24 3:06 p.m.

So I've been casually looking for an enclosed trailer for multiple reasons - 1) I'm always transporting a car, a tractor, or some other pile of E36 M3.  2) I already have a flatbed trailer for things like topsoil, mulch, and brush piles, and 3) I'm getting more into home renovations/flipping, and having all my tools in one mobile unit would be really nice.  Plus, it condenses all of my assets into one, easy-to-steal container, so if it gets nicked I can just live off an insurance check for a while.  (I'm kidding, but I do know it's a possibility.)

Used enclosed trailers hold their value.  For the price of buying a used enclosed, I could almost buy two new flatbeds.

So I had this dumb idea of taking a RV trailer frame and dropping a box from a box truck on it.  I always dismissed it because the weight of the box would eat up so much of my GVWR.  Turns out it might not.  Most of the 8.5 x 24' trailers I'm looking at are in the range of 3750 dry weight, and boxes seem to range anywhere from 3000-3500.  So even if an RV trailer frame weighs 1000 lbs (for a total of 4500 once joined) I theoretically still have 5500 lbs of payload to play with.  That's not that far off from the enclosed trailer's 6250 lb average.

Am I crazy?  I just found a 26' RV trailer frame with title for $100 (although, sadly, it's not a 10k gvwr) and I can usually find truck boxes for $1500.  Even if I find a trailer without a title, I have a 99% legal way of getting around that.

DeadSkunk  (Warren)
DeadSkunk (Warren) MegaDork
12/1/24 4:39 p.m.

I'd be surprised if the RV trailer frame was only 1000 pounds and strong enough. I'll bet it'll be closer to double that figure, I get what you're trying to do though. A 20 foot box @3000# and a 2000# trailer only leaves 2000# load cpacity on two 3500# axles. Are the RV trailer axles heavier than 3500?

 

Stampie
Stampie GRM+ Memberand MegaDork
12/1/24 4:41 p.m.

I got my enclosed 8.5x30 trailer for $2000.  Nothing else to add, I just wanted to rub that in.

sevenracer
sevenracer HalfDork
12/1/24 4:55 p.m.

Sorry to be Debbie downer but:

I think my cheapo 8.5X24 with 5k lb axles weighs closer to 5000 lbs.

Also, sounds like a lot of work to build out properly. Not sure if you are planning to put the whole box above the wheels or make inner fenders like a standard enclosed. but if the box is riding above the wheels, that would need some significant ramps to get to that height.

My first enclosed was not a car hauler, had barn doors - it sucked compared to a ramp door.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
12/1/24 5:07 p.m.
Stampie said:

I got my enclosed 8.5x30 trailer for $2000.  Nothing else to add, I just wanted to rub that in.

If only the forum didn't censor expletives :D

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
12/1/24 5:12 p.m.
DeadSkunk (Warren) said:

I'd be surprised if the RV trailer frame was only 1000 pounds and strong enough. I'll bet it'll be closer to double that figure, I get what you're trying to do though. A 20 foot box @3000# and a 2000# trailer only leaves 2000# load cpacity on two 3500# axles. Are the RV trailer axles heavier than 3500?

 

Many RV trailers (especially older ones, like before 2000) are often 10k if they're above about 28'.  I had a 2001 32-footer that was 10k.  My 1993 31-footer was 10k.  My current 5er is 28' and 10k.

The one I found is a 26-footer and it looks like twin 3500s, so not a viable option.

I'm not quite as concerned about the strength of the frame.  Have you seen the framework under a box truck container?  They're designed for forklifts, so no worries there.  The only real reason I think I would need an actual trailer is for title reasons.  Once that box is bolted on, the trailer frame is basically there for its hitch and a way to hold the axles in place.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
12/1/24 5:13 p.m.

In reply to sevenracer :

Not sure on the weight of yours, but I've been trolling the specs on a bunch of manufacturers' websites with specs on their trailers, and the heaviest 8.5 x 24 I found was just north of 4000 dry.

I would definitely cut wheel wells.  Even a stubby truck box is nearly 8' tall inside, and I want things close to the ground.

This is, of course, newer trailers that are likely made of tinfoil and hope, but just as a baseline.

Paul_VR6 (Forum Supporter)
Paul_VR6 (Forum Supporter) UltraDork
12/1/24 7:33 p.m.

I think its only wheel wells that are stopping those motivationally impared. 

My 10k gvwr enclosed 24' is 4500 unloaded so you seem about right. 

VolvoHeretic
VolvoHeretic GRM+ Memberand SuperDork
12/1/24 7:47 p.m.

To keep your new trailer from being stolen, just take off the tires and store them inside said new trailer at every stop? Treat it like a pit stop and see how fast you can get it done.smiley

Purple Frog
Purple Frog GRM+ Memberand Dork
12/1/24 8:01 p.m.

Just weld in sub frames with the two axles under the box, and a sub frame with hitch out the front.  Why use a whole trailer?

Rons
Rons GRM+ Memberand Dork
12/1/24 11:31 p.m.

In reply to Purple Frog :

Those boxes are somewhat less than robust. I play the home version of rig up that trailer on Highway Through Hell and you always hope you don't blow it apart.

dps214
dps214 SuperDork
12/2/24 12:47 a.m.

It just seems like a lot of effort to realistically not save all that much money and end up with an inferior product. Plus like you said trailers hold their value well. The up front cost is annoying but you're essentially just borrowing it until it's time to sell. With the diy version I doubt it would have much resale value, if any. So overall worse total cost of ownership.

93gsxturbo
93gsxturbo UberDork
12/2/24 1:49 p.m.

RV trailer frames are going to present challenges not present in enclosed trailers:

  • They are not made for heavy loading.  The box is heavy, the contents (mainly air) are not.  The load transfer is different.  
  • They are not made for continuous duty.  Most RVs are built around a 30 day/year duty cycle.
  • They are relatively high off the ground compared to an enclosed trailer due to the need for plumbing and storage underneath.  The trailer will end up high and awkward.

For $7-8k brand new, just buy brand new.  Even with $0 per hour time for construction, the cronenberg that is attempted to be constructed will be half that, and still need tires, paperwork, etc.  And it will be worth negative dollars if you ever decide to sell it.  

https://makemytrailer.com/8-5x24-enclosed-trailer/

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
12/3/24 6:47 p.m.
Purple Frog said:

Just weld in sub frames with the two axles under the box, and a sub frame with hitch out the front.  Why use a whole trailer?

They're beefy side to side, but they do rely on the truck frame for f/r rigidity.

Plus, here in PA there is no easy route to getting a title/registration for homemade trailers.  It's possible, and I've done it, but what a pain. It requires getting a VIN assigned (which is nearly impossible and the last time I did that I had to petition the court and get a court order), then getting a salvage certificate, then get an enhanced inspection, then apply for a rebuilt title. The only logical way is to start with a trailer that has a title.

I suppose I could build my own box, but time, labor, materials... I think I'm ahead to buy an existing box of some sort.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
12/3/24 6:57 p.m.
93gsxturbo said:

RV trailer frames are going to present challenges not present in enclosed trailers:

  • They are not made for heavy loading.  The box is heavy, the contents (mainly air) are not.  The load transfer is different.  
  • They are not made for continuous duty.  Most RVs are built around a 30 day/year duty cycle.
  • They are relatively high off the ground compared to an enclosed trailer due to the need for plumbing and storage underneath.  The trailer will end up high and awkward.

For $7-8k brand new, just buy brand new.  Even with $0 per hour time for construction, the cronenberg that is attempted to be constructed will be half that, and still need tires, paperwork, etc.  And it will be worth negative dollars if you ever decide to sell it.  

https://makemytrailer.com/8-5x24-enclosed-trailer/

While I agree somewhat, the older RVs are majorly beefy.  RVs since 2000 or so are pretty wussy, but for example:

This one started off as a toy hauler and has twin 6k axles.  The other candidate I have is a 32' Alumalite which has full length 8" I beams and 6" c-channel stringers.... but it's still a full RV, so too much work, and also a waste of a salvageable camper.

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
12/3/24 6:59 p.m.

But the Alumalite looks like this one, so not too high?

Curtis73 (Forum Supporter)
Curtis73 (Forum Supporter) GRM+ Memberand MegaDork
12/3/24 7:01 p.m.

The real bottom line is A) I don't trust an $8k new enclosed trailer when actual brand names I know and trust sell for $13-15k new.  Also, $8000 is about 4 times my budget.

I suppose I could trade my Lincoln for one.  Anyone interested in a 97 Lincoln Mk8 with 87k on it and every option?

93gsxturbo
93gsxturbo UberDork
12/6/24 8:58 a.m.
Curtis73 (Forum Supporter) said:

The real bottom line is A) I don't trust an $8k new enclosed trailer when actual brand names I know and trust sell for $13-15k new.  Also, $8000 is about 4 times my budget.

I suppose I could trade my Lincoln for one.  Anyone interested in a 97 Lincoln Mk8 with 87k on it and every option?

You crack me up, dude.  So you would trust a home-made bodge job more than a cheapo-depot factory built unit with a warranty?  

$2k budget?  Not seeing it for an enclosed, even a homebuilt.  Just tires and lights will chew up half that.  

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