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I'm taken with the idea of the Wide Path Camper, but not with the weight or the cost of getting one delivered to the US, so I was thinking it would be a fun project to try my hand at designing and building one.

I'm looking for information and/or experience on trailer design – especially the connection to the bike and considerations around the total weight of the trailer. I assume at some point it becomes important to put brakes on the trailer.

enter image description here enter image description here enter image description here

  • So what's your question ? I bought a trailer hitch for mine, didn't like the silly chainstay clamp. For brakes you can use overrun , with a master cylinder or with some caliper brakes, or you can use a two-cable pull brake handle, and run a tandem-length inner/outer brake wire down your bike and along the draw bar to a splitter. Overall weight should be low. – Criggie Jul 23 '16 at 5:48
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    Having browsed the website, I think its an idea whose time may not have arrived. I suggest you test the concept by building a suitably-sized trailer, then go tent camping with that. If you don't like the concept, at least you have a versatile trailer. If it all feels good. strap a huge cardboard box on your trailer and then go for a ride - see how the windage feels, and the lines of visibility, especially over your shoulder. Expect to do 1/3 to maybe a half of your normal riding speed, down to being blown backwards by a good headwind. If you go ahead, make the body separable from trailer – Criggie Jul 23 '16 at 7:32
  • a search for "build trailer" here finds quite a lot of answers, including a closed duplcate from someone who didn't have any real idea what they wanted. – Móż Jul 23 '16 at 9:04
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    There's quite a bit of elbow grease in that bike trailer. I don't think that you'd be able to best it in weight without reducing size considerably. And you'd easily spend more time designing/building/tooling than you'd spend delivering pizza to pay for it too. TBH, if you don't llike the weight, a bob with a big tent would probably be lighter, cheaper, and easier to manage. – david1024 Jul 23 '16 at 14:03
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    @Criggie, I'll work on improving the question – roughly speaking: what happens to the dynamics of the bike as a trailer load approaches a significant percentage of the weight of the bike and rider. – dlu Jul 23 '16 at 16:08
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There are a few of these trailers around, even some that are made in the US, including some from a company that sells multiple options (although they may have stopped, everything is out of stock on Amazon and not on their website). Most are DIY, and some have fairly detailed instructions available.

This how to make a cargo trailer question probably answers half of your question, so I'm going to focus on the other parts.

It's worth spending a lot of time reading and researching, and I suggest contacting people who have trailers like this and asking for their opinions. If you're lucky someone will give you one (admittedly in the "if you come and pick it up" sense), but that could be a good way to start your first camping holiday with it. Travel to the trailer with your bike, grab the trailer, then ride home. Sure, if it turns out to be a dumb idea you may want to abandon it after a few thousand kilometres, but that's cheaper and easier than building your own then discovering you don't like it.

I also suggest that you buy a standard bicycle cargo trailer first as they're much, much cheaper than any camper trailer that you buy or build. Tow that around for a bit, use it for your grocery shopping, take it camping. Think of it as a cheap testbed for your ideas about bike camping. Because it is. If you don't like towing the trailer, you find you can't easily tow even the 30-50kg those trailers are rated for, or you discover other problems, you won't have wasted much time or money on the camping trailer.

On that note, watch for the sunk cost fallacy, with other buyers and especially with DIY builders. DIY has an awful lot of "I built this, I put in a lot of work, it must be a great thing that I have built".

Materials

The Danish one looks as though it's rotomoulded, purely because getting something that big injection moulded would mean a million dollar mould. If you want that sort of custom plastic work done, it's going to be a lot cheaper to import one from Denmark than build it yourself. Even if you own a rotomoulding factory.

That means building it some other way. Corrugated plastic is easy to work with, fairly strong, resilient and cheap, and it also insulates more than nylon tent material does. But the easy way to do this is the buy a tent and put it on a trailer - that's what the "Kwik-Kamp" ones do. Heavier, but not much better, would be sheet metal, probably aluminium because it's easier to make things lightweight with it (steel can be just as light, but that takes more skill).

The choice really comes down to what you have available, and what you're comfortable working with. Being able to weld steel tubing will make the whole process much easier, even if you use plastic or wood as your sheet material. A steel chassis and hitch will be simpler than trying to build from other materials.

Design

I would start with a simple flat two wheeled trailer that can carry your camping gear. Go camping with that and see how you like towing a trailer. Then add 50kg of water to it (because water is cheap and easy to get), and go again. If you're not comfortable towing 100kg, the camper trailer is not for you.

Then I'd build a basic, big, trailer probably like my "megatrailer"

MegaTrailer by Moz

That was only 1.5m long, but it would be pretty easy to make one 2m long, enough to fit a narrow mattress on. You could even make a divan base for it to carry your stuff, or just a wooden base and a box on top, then strap the mattress on top of your stuff. As long as it doesn't rain. But this is a prototype. Maybe also do one trip with a fridge or oven box on top of the prototype, to give you an idea of how wind resistance will change before you get too carried away with building.

Once that works I'd add the real "camping box" to the design. I would be tempted to make a complex folding version just to keep the towed size down. Hinge across the back or front to halve the length, then tilt the front wall back to reduce air resistance, and if possible tilt the sides in too. Having flat walls that are trapezoidal, so the erected shape is a truncated rectangular pyramid, might make it possible to fold the walls completely flat while travelling.

One variant of that would be to find a tent that is the right size and shape for your trailer, build a topless box base that's the size of the tent, then glue the bottom of the tent to the base and cut the floor out. That way you have a fairly waterproof cover for your box, and it should be easier to set the tent up than without the trailer. Downside is you're still sleeping in a tent.

I would be tempted to push the "box" up a bit, possibly to around a metre. That way you have enough structure to lean on the fixed wall while you're sitting in it, and with a bit of design effort it could still be fairly aerodynamic. You could possibly do a "pop top" style camper based on that, or the more modern wall lift variant - two boxes that nest, so when you lift the outer one that is the roof, it exposes more and more of the inner walls until eventually you reach the join and it's fully erect. That gives you completely solid walls and potentially a very weather-resistant design, but obviously at a significant weight penalty.

Another option would be to copy the A frame style pop top campers

enter image description here

That has the advantage that you know the design works, but it would need to be fairly large to give you enough headroom. But possibly you could vary that design so that it worked better in small scale.

Wheel Size

There's a good reason why the Wide Path photos show 406 wheels all round. Trailer wheels, and the rear wheel of the towing bike, experience significantly more side forces than most bike wheels. You will need to take that into account. I use 406 wheels for most of my bikes for this reason, and also partly because it's a good idea to pick a size and stick with it. Having to carry two sizes of spare tyres and tubes while touring is just annoying.

To get the lateral strength you can either make the wheel smaller (406 size), the flanges bigger or the hub wider. Fatbikes, IGH and motorised hubs are other solutions to that problem. You can, of course, combine them - a fatbike with 406 wheels and hub motors might barely have spokes at all, so getting strong wheels would be easy (lacing them up, maybe not so much)

Power Assist

One option would be to design it around 300-500W of solar panels, and use an electric bike to tow it. That way you can go further, faster with the trailer and as a free bonus you have power when you're camping (not much, but charging phones etc will be easy, and you'll be able to run a light).

I met a guy who is riding around remote bits of Australia using a fatbike and a trailer load of panels. He uses a tent, but the idea is there.

Solar Shift bike and trailer

Travel Limitations As you've already realised, you're not going to be taking this on a plane or bus. Ever.

Size is going to be an issue in other places too, unless you already know everywhere you want to take it and know that there will be metre-wide gaps everywhere. Unfortunately many "bicycle facilities" have barriers specifically to stop vehicles that are wider or longer than a normal bicycle from using the facility. So if your design is wider than the usual 800mm or so bicycle, you either need to be able to lift it over a 1.5m high fence, or roll it backwards until you can find somewhere to turn round.

The fact that most camping trailers can't do that makes me wonder how serious the owners are about cycling - I suspect that most owners ride short distances on flat ground on known roads. If that's what you want, this could work really well.

Other Random Observations

I've done a bit of cycle touring on odd bikes, including a tandem recumbent trike, and on one trip I had both the trike and megatrailer. We quickly discovered that with the trailer our speed dropped from about 20kph to about 10-12kph, and the other cyclists were generally no faster with the trailer (they were usually faster than the trike without it). Touring with a big, heavy bike starts to get tedious after a while.

Sam, the solar trailer guy above, started out with a home-made tadpole solar power-assisted trike. After a few thousand kilometres he decided that he really, really wanted something that could detach from the solar panels and be ridden independently. Your camping trailer will have that advantage, but it's worth keeping in mind that you will want to lock and leave the trailer at times. Resist the urge to build a heavily customised towing bike that is hard to ride without power assist.

But you may well find that you're better off with a custom towing bike. Lacing narrow-ish rims onto fatbike hubs will give you unreasonably strong wheels, and with the camper putting big side loads on your rear wheel that may be really useful. You might also find a Pinion bottom bracket gearing setup solves a lot of problems around where you attach the trailer, and how you get the extra-wide range of gears you will hopefully need (if you're unlucky it will handle so badly that typical MTB gears, only with unusually small chainrings, is ample for the 0..20kph speeds your rig is capable of).

Designing it to be dismantle-able into bits that can be shipped might be well worth while. Not so much "easy to reassemble" but just "break it down, ship it home, get on the bus, worry about it when I get there" scenarios. You'll possibly only do that once, but if you do need to bail on a ride not needing to hire a box trailer or truck to move it may greatly simplify things. It's better than just setting fire to it, however good that might feel at the time.

Finally, I do think this could be a really good project, but I would suggest testing your "tow a big heavy trailer on tour" abilities first before committing too far to the idea.

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    I would think one of the cheaper two-wheeled plain trailers would be a good starting point for an initial test prototype. They can be had for less than $100 US and will include a good example of how not to construct a hitch. – david1024 Jul 23 '16 at 14:17
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    Thank you! Your testing ideas are most useful, as is your insight about the loads on the rear wheels. – dlu Jul 23 '16 at 16:06
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    Plus 1 and a shame I can only give one. Good solid advise in many different fields. Having used (with great pleasure) a rather heavy recumbent trike with a low top speed (due to gearing) I know the feeling of being slow on longer rides. it is something you have to get used to or it might stop you using the bike/combination. – Willeke Jul 23 '16 at 17:59
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"what happens to the dynamics of the bike as a trailer load approaches a significant percentage of the weight of the bike and rider?"

I have one of those two-wheel two-kid trailers/prams that are about the cheapest thing you can buy.

From my personal experience, there are four main factors

  1. Windage This thing folds flat which helps, but when fully assembled its presenting at least a square metre of frontage area. That's roughly the same as a sail the size of a bath towel. That's a good-sized sail and will increase the effect of normal winds and draughts from passing vehicles.

  2. Weight Empty this trailer weighs about 8 kilos. So its half the bike weight again. I've had it loaded up with 50 kilos of tools and bike parts, and while its manageable, I can feel it dropping into any holes through the trailer coupling and the bike's frame.

  3. Rolling Resistance You're now hauling two or more additional contact points with the ground. It adds resistance

  4. Momentum This is proportional to weight. If you get the whole rig up to 20 km/h then on the same brakes you'll have additional stopping distance. In addition, the trailer will push you while you're braking.

enter image description here

I had an unpleasant stop which was almost a jack-knife. Riding along with the 50 kg load at about 20 km/h, approaching traffic lights that turned yellow. I was going too slow to make it across, so I braked to stop. The trailer is unbraked, and it managed to lift the rear wheel off the ground and push the back of the bike sideways by 10-15 cm. Most of my braking effort was on the front wheel, so the rear would have been unloaded. This whole push combined to try and throw the bike on its side. Fortunately I steered into the "turn" and recovered without a fall, but I'm sure it wasn't graceful!

On the plus side, most cars tend to give you a lot more space. I've seen thundering-great Fonterra milk tankers drive clear on the other side of a two way road to provide extra space.

You should borrow a trailer and try it out with a big box and weigh it down with water bottles to replicate your plan. Then ride up and down a hill to see how it feels, before you spend big money.

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    When braking with a heavy trailer, it may be worth it to shift your body weight way back, sit down behind the saddle onto the carrier or the connection between bike and trailer. – Nobody Jul 24 '16 at 10:14
  • @Nobody Or ride slower to allow for the extra stopping distance. – Criggie Jul 24 '16 at 10:23
  • This would be the best solution of course, but for example when riding downhill with too much weight then it may not be possible. – Nobody Jul 24 '16 at 10:48
  • @nobody If you're in that position you've already made your mistakes and have to cope as well as possible. Better to anticipate and avoid the problem, hence braking on the trailer for heavy loads. – Criggie Jul 24 '16 at 11:05
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Some thoughts, not really a complete answer:

  • this ideally needs extra brakes
  • maybe rectangle frame made from tubing, 2m x 60cm at some 20-30 cm distance from the ground
  • fix a kind of tightly strung hammock into the frame instead of carrying a mattress. In winter put a thin isolation matress on top
  • add a row of bags beneath the frame, accessible from both sides, maybe 5 bags each 40cm wide and the whole 60cm across, hanging down 10 to 20cm
  • build a tunnel tent on top, maybe 3 tent poles which attach to the sides of the frame at the front, back and middle
  • make it so that you can remove the tent poles to travel, leaving the fabric on and binding it down with some ropes/bands, protecting and securing additional luggage which you leave beneath it
  • to better secure the tent in stormy conditions, add extensible pieces of tubing at the front and back so that you can extend them like 50cm out in both directions and fix them and add ropes from the end of the roof of the tent to the end of those extensions.
  • bonus if the tent doesn't directly fix to the sides of the frame, but onto extensible pieces some 10cm out and below the frame so you get airflow but are still protected from wind

If I had time I would love to build something like this. I think it could be done lightweight enough to make it actually practical for long tours. Those trailers which are more like traditional caravans are way too heavy.

  • You're onto it - is more like a half-setup campsite on a trailer than a caravan. I'd be staking down the trailer at night though - one good gust of wind could put the whole tent/trailer over. You could store your bike under the trailer for some shelter too. – Criggie Jul 24 '16 at 19:56
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    Yes, half-setup campsite is what it would be, exactly. :-) You are right about staking it down, although I had a relatively low tent in mind (say 60cm high in the middle) which I think would be weighted down enough by 70kg of person and 60kg of luggage and trailer so it would probably topple over while the owner is away in the showers or something, not while asleep in the tent. I don't know enough about tunnel tents, could be that it's not even possible to make them much higher in relation to tunnel width. – Nobody Jul 24 '16 at 20:59

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