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  1. #1
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    Default Feasibility of dual axles and different weight distributions

    I want two trailers. A box and a teardrop-style camper. The former has conventional axle placement if a single. The latter requires it way back if a single. Does the forum think it would be feasible to have one chassis and two bodies, and swap bodies as required. I would then try to have tandem axles in a position that balances the two requirements i.e. one roughly where a box single would be, one roughly where a teardrop single would be (or as close as possible given tandem configuration). Does that make sense?

    I'd have to deal with a much heavier than normal chassis but the benefit would be versatility and not having to store two full trailers (I could use a roof pulley system to hang the unused body off).

    Just an idea I had, feel free to tell me how stupid it is.

  2. #2
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    jatt is offline Always within 10 paces from nearest stubby holder
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    See plenty of folks who use a single axle box trailer and drop a tent trailer bed base (complete with tent) on top for camping duties. guess you could drop a teardrop box on top with a little thought. Just think your weight and its distribution thru, esp on single axle.

    Flat top with removable sides to make it a box?! like a tray ute. Drop teardrop assy an top?

    Storage sounds like it could be a bugger 4 ya. A lean to on outside of shed for one of them?

    Mind you most folks just have em out in the yard; I do.

    Been meaning to build another "canvas" shed next to the main one. Another 4 the ever increasing to do list. trouble is my stuff will be booted out for customer stuff that leaks like a sieve!!!!!

    Enuf of the Bourbon induced ramblings, hopefully some stuff to contemplate.
    Frisky wife, happy life. ​Then I woke up. Oh well it was fun while it lasted.
    From an early age my father taught me to wear welding gloves . "Its not to protect your hands son, its to put out the fire when u set yourself alight".

  3. #3
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    Legion, are you planning to make the teardrop yourself????
    jatt has the right idea of using a trailer base for both units, sides that can slip in and out as per the semi trailer gates, the tailgates hinge on the base of the trailer as per normal, holding everything together. Just need to check DMV if that sort of thing is allowed, as sometimes a trailer and a caravan, are 2 different things in their eyes.
    The teardrop could then fit straight on, once the sides are taken off, requiring only minimal storage space.
    If it was necessary to adjust the trailer axle, this could be set up similar to a boat trailer, the suspension mounted to the angle iron, which then bolts to the sides of the trailer chassis.
    Water tanks could be set up under the trailer, and left permanently under there, requiring only the hose/s to be hooked up.
    Kryn
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  4. #4
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    Yeah I Kryn I'd do it myself. Ally frame, ally skin, foam insulation and possibly light timber on the inside for aesthetics. I have almost zero ally experience but my steel and stainless skills are strong. Great opportunity to learn. Probably on the box first, camper second.

    I'd do an annoying custom three-link (trailing arms + panhard), solid axle with airbags so it'd be easier to not move. I could have it on a subframe but there would be seven mounting points (each trailing arm, panhard, two bags, two shocks).

    But you guys have me thinking. If I put the box rearwards when it's on, balanced with respect to the axle, it'll still have plenty of down weight due to the chassis/axle placement but should be more balanced.

    Good point on licencing. I thought I'd get it done as one or the other and it'd be fine but I'll check.

    Definitely prefer single axle if i can get away with it.

  5. #5
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    DVM -- good point.

    Recon some thought needs to be done before firing up the welder.

    As far As i can see, the main difference between a "closed in box/ teardrop... call it whatever u darn well like", and a caravan is the power and gas side of things.

    Whilst you are doing your homework, the rules wrt lites "clearance etc... "need to be understood. A multiway (trailer socket/plug) may be your answer here.

    If I keep this up I will have the thing designed as well
    Frisky wife, happy life. ​Then I woke up. Oh well it was fun while it lasted.
    From an early age my father taught me to wear welding gloves . "Its not to protect your hands son, its to put out the fire when u set yourself alight".

  6. #6
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    You have a couple of issues here.

    The biggest is the compliance and regestration ....... the legal system simply does not accomodate 1 chassis with 2 boddies ....... I know a bloke who did it may years ago with a single chassis and a bot trailer & bike trailer body....... bit it is just not practical.

    What is practical is to have a permament box trailer body with a camper carried as a "load".

    I know the teardrop rtailer concept is attractive and seductive .....but it's advantaged go away if it is not built as a trailer in its own right.

    It is however very practical to build a curved body or a curved canopy.

    If building on top of a box you are better with a rear entry, because the low access already exists, you can spread the body out over the top of the wheels, giving much more width inside.
    Instead of building the kitchen at the rear, it can come out the front.

    Another very practical option is to build a pantech type canopy with a roofrack ..... which will be very practical day to day, and fit a roof top tent opening out over the rear....... this gives you all the storage space in the trailer or the ability to sleep 4.

    cheers
    Any thing with sharp teeth eats meat.
    Most powertools have sharp teeth.
    People are made of meat.
    Abrasives can be just as dangerous as a blade.....and 10 times more painfull.

  7. #7
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    That actually fits with one of the teardrops that is pretty inspirational:



    If you search "crowswing teardrop" they have (very) detailed build threads at expeditionportal and tnttt. That would fit on a box, although with landcruiser matching wheels my idea would sit a lot, lot higher. Probably be a 10' high van, that'd be fun.

    A Moby XTR is what I really like the look of, but that wouldn't go with the box and would require a dedicated chassis I reckon:



    Good lateral thinking though soundman and gives me a direction to investigate (kitchen at the front and entry through the back. No roof top tents though, or any exposed canvas except shade. We do tents now and when it's 15kt+ the fun of coastal camping disappears.

  8. #8
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    The traditional idea of a teardrop camper is quite limited and has some fundamental flaws.

    It was originally designed to be a very light weight camper to be towed by small 4 cylinder sports cars and very small sedans, Like, MG midgets, healy sprites and A40s.

    As soon as the size height and weight gets up the flaws in the format become serious problems.

    The single biggest flaw is the heavy rear kitchen ( people want a lot of stuff in their kitchen these days) with a high centre of gravity ..... no matter where you put the axle it will always create a tail wagging stability issue.

    If you pretty much ignore the whole teardrop concept apart from the curved front then a whole pile of things become possible and practical.

    One of the problems I see all over the place is this building out into the drawbar or putting boxes on the drawbar.

    It is utterly impractical when you have a rear loading tow vehicle with a tailgate.
    The other thing that putting load on the drawbar does is seperate more and more mass away from the axle.

    The more mass that is concentrated low and central close to the trailer axle the more fundamentally stable the trailer will be ...... the more mass you place at the extremities of the trailer the more you compomise the stability.... regardless of how it is balanced or where the axle is located.
    In addition the more storage you have at extremities, the more filling and emptying that storage effects the balance and dynamics of the trailer

    SO
    building on a coventionally shaped box trailer with the axle only slightly behind the centre of the box.

    Start by building the sleeping platform level with the top of the trailer tub.
    This gives quite a lot of storage space low in the trailer tub.

    Building a kitchen that pulls out onto the drawbar ...... like a replacement for a front tailgate ... alows all the kitchen mass to be returned into the main body of the trailer low and close to the axle.

    A fairly large water tank could be fitted dead centre above the axle, alowing the kitchen to stow in front and general storage from the rear ...... filling and emptying the water tank would not effect balance or dynamic behaviour .... spare tyre could be slung under the rear on a tyre winch or carrier from a ute of your choice.

    A kitchen loading from the frontand a sleeping entrance from the back is most advantageous for short stops and lunches.

    an roll up awning front and rear could be used with or without the vehicle attached

    If you like the teardrop look ..well curve the front and back ...... the curve at the front achieves better airflow ...... the curve at the back realy achieves very little unless the whole thing is a traditional teardrop and towed by a vehicle that is already low and aerodynamic.

    cheers
    Any thing with sharp teeth eats meat.
    Most powertools have sharp teeth.
    People are made of meat.
    Abrasives can be just as dangerous as a blade.....and 10 times more painfull.

  9. #9
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    Quote Originally Posted by soundman View Post
    It was originally designed to be a very light weight camper to be towed by small 4 cylinder sports cars and very small sedans, Like, MG midgets, healy sprites and A40s.
    So not a 2.5 tonne Landcruiser then?

    Some very good points soundman. Thanks, it's much appreciated.

  10. #10
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    I'm wondering if you could build and register a trailer that was essentially just a chassis? Boat trailers are pretty much that, as are bike trailers - just specialised trailers that meet what's set out in VSB1.

    Provided whatever load that's put on there doesn't exceed the specified mass, I'm not sure what the issue would be?

  11. #11
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    there are specific catagories of trailer ...... boat trailer is it's own catagory.

    besides, if you build a chassis on its own it has to be much heavier than if the tub is part of the structure.

    realy there would not be much to gain.

    cheers
    Any thing with sharp teeth eats meat.
    Most powertools have sharp teeth.
    People are made of meat.
    Abrasives can be just as dangerous as a blade.....and 10 times more painfull.

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