Teardrops n Tiny Travel Trailers

Posted: **Sat Jul 24, 2021 8:14 pm**

Now for the fun part.
With some discussions here and other forums I decided to try a different approach for the floor. I am going to try to make a floor with 2" foam sandwiched of course with canvas on both sides. There will be a spine down the middle that will connect the hitch to the axle so I think it should be plenty strong enough.

Here is the floor getting cut out.

: Cutting out the new foam floor; 20210724_074748_HDR s.jpg (477.74 KiB) Viewed 1241 times

I cut dado's along the sides. This is where the walls will bed into the floor since I am doing away with the inner frame rails. Inner frame rails would be hard to install in foam anyway.

: Wall dado; 20210724_092854 s.jpg (408.09 KiB) Viewed 1241 times

I am painting both sides of the floor with bonding primer before applying the canvas.

: Bonding primer; 20210724_115835_HDR s.jpg (471.31 KiB) Viewed 1241 times

so I weighed the foam floor and it weighs 4lbs at this point. That is 29lbs. lighter than the OSB floor I made already. I hope this works well because that might get me in under 50lbs. for the complete build.

Well I am waiting for canvas to dry as I type. Hope to get the other side of the floor done tomorrow morning so I can start piecing this thing together.

Posted: **Sat Jul 24, 2021 9:01 pm**

ghcoe wrote:Well I am waiting for canvas to dry as I type. Hope to get the other side of the floor done tomorrow morning so I can start piecing this thing together.

Looks good. How tall will it be? Thinking about cross winds...

Posted: **Sat Jul 24, 2021 9:34 pm**

probably about 58" total. It does seem like quite a bit of exposed sidewall, but it is in line with European commercial and home builds that I could find. There are some units that have pop ups, but I am not a big fan of pop ups. To me they seem flimsy, with too many places for water, wind, bugs to get in.

Posted: **Sun Jul 25, 2021 3:05 pm**

Ooh, this is interesting. AM i correct in assuming you used 1 inch thick foam for the walls ?

Covering the floor with 1/8 inch to give it a bit of protection will still save you over 20 pounds on the osb floor, no ?

Posted: **Sun Jul 25, 2021 3:29 pm**

woodie72 wrote:Ooh, this is interesting. AM i correct in assuming you used 1 inch thick foam for the walls ?

Covering the floor with 1/8 inch to give it a bit of protection will still save you over 20 pounds on the osb floor, no ?

Yes easy.

I just weighed the floor with both sides canvas and it was 8.5lbs. I tested the strength by placing some supports under the wall areas and it held my weight no problem. There will be a small frame that will run down the middle to attach the hitch and axle together. This will also help with supporting weight in the center.

I will be adding 1/2" high density foam to the floor. I think at this time that it should protect the floor enough to keep it from denting with pressure points. I like the 1/2" foam because it holds cargo in place well and is comfortable to move around on.

I weighed everything individually and at this point it looks to be about 45lbs. That gives me 5lbs for exterior glue and paint. If I calculated it correctly it should be right at 50lbs. If not is should be well under 60lbs. Not bad since I was starting at 100lbs.

Posted: **Mon Jul 26, 2021 4:42 am**

With high density foam, do you mean something like evazote ?

Just a thought, might epoxy glued and finished 1/4 inch rolled cork be a little sitffer than the foam ? :thinking:

Hope you will post some picture of the framing in the floor.

I am thinking about a solar trailer combined with a possible sleeping arangment for my diy folding ebike conversion, of which i yesterday smoked the controller :roll:

Posted: **Mon Jul 26, 2021 5:06 pm**

woodie72 wrote:With high density foam, do you mean something like evazote ?

Just a thought, might epoxy glued and finished 1/4 inch rolled cork be a little sitffer than the foam ?

Hope you will post some picture of the framing in the floor.

I am thinking about a solar trailer combined with a possible sleeping arangment for my diy folding ebike conversion, of which i yesterday smoked the controller

The high density foam I use on the floors I pick up at Harbor Freight. It is foam that locks together to be put on hard floors to alleviate foot and leg discomfort.

Not sure about the cork. Have not played with that idea, but I do tend to stay away from epoxies. I don't particularly like working with them.

The framing will be under the floor and will run from the hitch to the axle. Not sure of the material at this point could be wood or aluminum or a combination of the two. I will post up pictures here when I get to that point of the build.

Posted: **Tue Jul 27, 2021 11:48 am**

Make sure that the hitch bar is stiff enough and strong enough not to break. I used 1" square tube aluminum and it is too flexible. I think I can reinforce it but I have only used my trailer to sleep in the back yard, so I don't tow it much.

Posted: **Tue Jul 27, 2021 4:22 pm**

skyl4rk wrote:Make sure that the hitch bar is stiff enough and strong enough not to break. I used 1" square tube aluminum and it is too flexible. I think I can reinforce it but I have only used my trailer to sleep in the back yard, so I don't tow it much.

Well I was thinking a 2"x2" or 1" aluminum tube. The aluminum did seem to flex a bit when I was testing it at the store, but I think it should be ok for this build. A foamie is quite rigid when it is all glued together like a unibody. With the 2" canvas covered floor with a span of only 40", the aluminum would be more for pulling forces than for load bearing. Of course that is just a theory at this point. :thinking:

You have a picture of your build? :pictures:

Posted: **Tue Jul 27, 2021 4:33 pm**

Is that Hot wire cut ?
:awesome:

Posted: **Tue Jul 27, 2021 7:32 pm**

twisted lines wrote:Is that Hot wire cut ?

Yes, all the cuts in the foam are hot wired.

Posted: **Wed Jul 28, 2021 1:04 pm**

ghcoe wrote:
skyl4rk wrote:Make sure that the hitch bar is stiff enough and strong enough not to break. I used 1" square tube aluminum and it is too flexible. I think I can reinforce it but I have only used my trailer to sleep in the back yard, so I don't tow it much.

Well I was thinking a 2"x2" or 1" aluminum tube. The aluminum did seem to flex a bit when I was testing it at the store, but I think it should be ok for this build. A foamie is quite rigid when it is all glued together like a unibody. With the 2" canvas covered floor with a span of only 40", the aluminum would be more for pulling forces than for load bearing. Of course that is just a theory at this point.

You have a picture of your build?

viewtopic.php?f=24&t=72251&start=15#p1256891

Posted: **Wed Jul 28, 2021 6:35 pm**

Ah! Yes I think I stumbled upon this build in my researching. :thumbsup:

Posted: **Fri Jul 30, 2021 8:44 pm**

Looking good.
This is great exploratory work for developing a small lightweight trailer with aspects that can be incorporated into a larger yet small teardrop for max lightweight.

Sub 50lb, maybe even 40 or 35 are great targets for a cycle trailer. What are the euro bike trailer weight ranges?

Thoughts
Narrower wedge shape?
PMF necessary to save weight?
Minimize walls and roof weight with 1/2 inch xps and light canvas for PMF?

On this build since it is for a cycle trailer, everything needs to be assessed for max lightweight/ minimal size to reduce drag and weight.
My thoughts are minimal overall size. In other words not built to space convenience or roominess but more custom sized exactly to owner physical size.
From my experience having used a 24 inch bed travelling in a minivan for 4 yrs, the width of the trailer can be narrower reducing weight. Thinking 30 to 36 wide external. Length equivalent to maybe 6 inches longer than owner. Storage on shelves on side in top corners.
Height again 2 to 6 inches taller than situp height. Possibly angled low at front up to back. Basically a wedge coffin. :lol:

Even though this is for an electric bike, they are very limited in range without adding extra weight and aerodynamic drag. That article about the electric bike race with solar to China still highlights that they still required 50% human power even with electric and solar panels telling me that weight and drag still major restrictions.
Weight and size are enemies to human powered (and even electric assist) and it's a great engineering challenge to build max light and yet sufficiently strong to accomplish the task.

Realize that this is a contract job for you, yet interesting engineering challenge. :thumbsup:

Posted: **Fri Jul 30, 2021 10:25 pm**

Terra6 wrote:Looking good.
This is great exploratory work for developing a small lightweight trailer with aspects that can be incorporated into a larger yet small teardrop for max lightweight.

Sub 50lb, maybe even 40 or 35 are great targets for a cycle trailer. What are the euro bike trailer weight ranges?

Thoughts
Narrower wedge shape?
PMF necessary to save weight?
Minimize walls and roof weight with 1/2 inch xps and light canvas for PMF?

On this build since it is for a cycle trailer, everything needs to be assessed for max lightweight/ minimal size to reduce drag and weight.
My thoughts are minimal overall size. In other words not built to space convenience or roominess but more custom sized exactly to owner physical size.
From my experience having used a 24 inch bed travelling in a minivan for 4 yrs, the width of the trailer can be narrower reducing weight. Thinking 30 to 36 wide external. Length equivalent to maybe 6 inches longer than owner. Storage on shelves on side in top corners.
Height again 2 to 6 inches taller than situp height. Possibly angled low at front up to back. Basically a wedge coffin.

Even though this is for an electric bike, they are very limited in range without adding extra weight and aerodynamic drag. That article about the electric bike race with solar to China still highlights that they still required 50% human power even with electric and solar panels telling me that weight and drag still major restrictions.
Weight and size are enemies to human powered (and even electric assist) and it's a great engineering challenge to build max light and yet sufficiently strong to accomplish the task.

Realize that this is a contract job for you, yet interesting engineering challenge.

Yeah the European trailers don't share their weights in most cases. The only one that gave me a idea was this one https://scout-camper.de/en/home/ showing 47kgs (103lbs.) If that one weighs that much I would venture to say this one is https://widepathcamper.com/bicycle-camper/ in the 150lbs range easy. The person that wanted me to build this one wanted it 100lbs or lighter so I gave up at first once I knew I was under 100lbs. Now it is a challenge to see how low I can go and still make a comfortable trailer. There is a teardrop style bicycle trailer being built too http://mody-plast.de/produkte/fahrradwohnwagen/ . I see on another site that it weighs 92-110lbs depending on options. So I believe I am in a good spot weight wise.

My dimensions are pretty close to what is being built in Europe, as well as DIY builds, although there does not seem to be a standard by any means. I came up with the wedge shape for a couple of reasons. First a boat goes through the water pretty good so flip it over to cut through the air. No front wall to hit something that would throw you over the handlebars, also to deflect impacts to the sides making it easier to recover. If you have a head wind the front will cut through the wind. If you have a tail wind the back flat wall will act as a sail to help push you along. Not sure about side winds at this point. Here is another similar sized trailer like I am building http://www.bicyclecaravan.com/bicycle-c ... trailer-2/.

I am making the sidewalls out of 1" and the floor at this point with 2". PMF will have to applied to add the strength and protection to the foam.

The client wanted something fairly large. I do believe this trailer will be close to the size they would like since they referenced the trailers above as a guide for me. They wanted something to be able to sit comfortably in and store some items for travel. We also talked about solar and extra battery in the trailer. Basically one battery can be charging while they used the other. This is planned to be pulled behind a high dollar cargo e-bike so I am not sure of it's capabilities.

I hope to get the walls up tomorrow.

Teardrops n Tiny Travel Trailers

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