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common questions


Do you have a non-welded version of this trailer?

I made plans for a bolt-together trailer once long ago, and they are included in the "Deep and Short" manual that can be downloaded on this site. However, I like Carry Freedom's Bamboo trailer plans much more. The website http://carryfreedom.com/bamboo.html has instructions for downloading plans. Nick is the designer, and shares plans openly. You can build these trailers with anything from bamboo to EMT conduit, using a variety of joining methods like bolting or lashing.

Do you have a heavy-duty model? What about building in less-industrialized environments?

Yes, in the works. I'm working on a plans for a design for a trailer that is stronger, heavier, and larger, that attaches to a seatpost of a bicycle, and is easier to build and repair in less industrially developed parts of the world. I've been calling them the "bicycling empowerment trailer" or BET, and although I haven't finished the plans yet, you can email me for a draft if you like.

Can I carry Passengers with these trailers?

Partly as a liability concern, and partly as a safety concern, these trailers are not designed for passenger transport. Please read:

These trailers are not designed for carrying passengers. Several safety considerations arise, including tip-over safety, weight distribution, guards to prevent hands and feet from contacting the wheels and ground, etc. If you would like to build a passenger carrying trailer please feel welcome to look at my designs as guidelines, but please don't consider these trailers suitable for passenger use as I've designed them.

There is an ASTM document that regulates the design of passenger carrying bicycle trailers that describes safety concerns in further depth: ASTM F1975 - 09

There are numerous companies that are making bicycle pedicabs and rickshaw around the world, and a few companies that make bicycle trailers as mobility aids. They have addressed passenger safety and would be good places to look for information.


These "flatsy" and DS trailers are NOT designed for carrying passengers, but here's a link to a photo of a taxi trailer that I built in Namibia. It works fairly well, though of course its not finished in this photo. Add fenders and a backrest, some paint, and a good fender for the bicycle's rear wheel and it will be a pretty good taxi.
Namibia taxi prototype

Where are these trailers designed to be built?

I designed these trailers for "garage production" in the USA, where I know what tools and materials are widely available. The dimensions are largely based on the 4 1/2 inch bend radius of a 1/2" EMT conduit bender. If you are building in a location with different size benders and tubing, you may consider checking the dimensions before bending and cutting. I'll publish dimensioned drawings and a guide for bend calculations soon, sooner if enough people email me telling me to hurry up.

Will you help connect me with other people near me building trailers?

Yes, I can try. Email me if you want this expedited. I'm looking for someone to help me develop a tool for social networking people who ask me to connect them with other folks in their area, without creating any unwanted communication. Any ideas for this? Email me...

What about single-wheel trailers, boat trailers, ice cream carts, etc?

I would like to develop a single wheel trailer and publish plans. Let me know if you want to help of if you have ideas for building them. I tend not to use trailers very often, preferring an Xtracycle cargo bicycle because of the maneuverability in cities, but a single wheeled trailer would be useful for me. When I get time....

Ice cream tricycles, and selling things from bikes: I'm thinking about creating a photo gallery of different designs. Nothing yet though, but www.zerocouriers.com/workbike/ is a great resource.

Canoe and Kayak trailers: Make a padded cradle for your boat out of conduit that rises up from the mainframe on the "Flatsy" trailer, either using only the wheelwells for small boats, or additional cradles in the front and rear for larger boats. Make a longer pulling arm, using 3/4" EMT (1" OD) doubled vertically for runs longer than 5 feet.

What can I do to help your project?

Thanks for asking! I'm pretty hopelessly behind of replying to people's comments at the plans download page....and hoping someone can help develop bits of php to make it easier to reply personally.

I'm also hoping to make a fabrication instruction video for the flatsy trailer, kind of like I made for the bicycle ambulance at http://vimeo.com/1804071, but easier to follow. Anyone in the bay area want to help with filming, and anyone anywhere want to help with editing? I'm looking for someone who's already comfortable with video who has a little time for volunteer--this project is entirely volunteer run (only me so far).

You could also donate to the project--I use these donations to print and distribute free paper copies of the fabrication plans, and sometimes to buy materials for free how-to-build-a-trailer workshops.

Support this project

Who are you? Why do you do this?

I began this project as coursework at Hampshire College, when I was beginning to study "Appropriate Technology". The class was working on a project for a bicycle ambulance in rural Malawi, and at a certain point I realized that I didn't know enough about the use conditions, fabrication environment, materials availability, or cultural considerations to feel comfortable, on a personal level, working on the project in a classroom environment. I decided to design a bicycle trailer that could be built in communities that I was a part of, and to which I was accountable. I've worked on the project since then, off and on, as I have time. I get personal encouragement from the notes that some people leave when they download fabrication plans, which encourages me to keep on designing and writing up plans.

At the moment I live in the bay area of California, and I've lived in Vermont, Alaska, Windoek Namibia, and Northampton Massachusetts.

What about production beyond weekend projects? Can I build these and sell them?

For building to sell, go for it. However, these trailers are designed for low volumes--they are best for fabricators with limited experience, but a lot of time to bend and check and miter and check again, etc. Folks who have made these in quantity to sell( in the US, at least) have done it for the love of building trailers and helping their communities move towards car independence and accessible transport.

Feel free to build and sell these trailers as you like, but please include a copy of the fabrication plans when you sell them, to let people know about this project. A fair price? People have sold flatsy trailers from $60 to $200. I'm interested in affordable trailers being out on the road, which can happen from the combination of a low price for a customer with a fair price for the builder. Let me know how things go if you do build to sell.

I am thinking about creating a manufacture package for a manufacturable trailer I would design--and publishing it open source. This could be a set of plans for the trailer, a list of suppliers for wheels, and a set of drawings for production fixtures (tools) to build the trailers without measuring and doing complicated layout for each one. This could help folks have businesses building low-cost trailers on a small manufactured scale, favoring local production again. On a personal level, transitioning this project from DIY support, to working to support manufacture is a large transition, and raises questions for me about about how I want to engage with supporting even small scale industrialization, globalization, and private sector manufacture.

I'm currently building experience with manufacturing at my day job, so I might be able to apply some of this information, mixed with a philosophy of open-source design and local accountability, to a new model of socially-just and responsible manufacture, if it may be possible.

email aaron
this is an open source design.
make a bike cart. use it. then make another one to give to a friend.

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