Introduction: CSA and Compost Bicycle Trailer

The CSA / Compost Bike Trailer project addresses the underutilized potential of
the bicycle as a cargo carrying transportation device in the urban landscape of New York
City. Implemented in order to meet the local transportation needs of the Ditmas Park
CSA and Compost for Brooklyn, the CSA / Compost Bike Trailer ultimately seeks to
connect and build relationships between environmentally minded groups and individuals
in the Brooklyn neighborhood of Ditmas Park by helping them work together to make our
food cycle healthier and more sustainable.

The final iteration of the CSA / Compost Bike Trailer meets the needs of all
programmatic elements required by the Ditmas Park community groups involved
and ultimately is designed to be reconstructed many times over by groups in other
neighborhoods with similar needs. To pursue this goal a detailed set of free construction
documents has been made available online and all materials used to make the bike trailer
are easily and inexpensively accessible at local hardware stores. It is our hope that the
CSA / Compost Bike Trailer will ultimately connect people within the communities
it functions within, promoting a healthier food cycle and the bicycle as a viable cargo
carrying transportation device in the urban city environment.

by Pavel Mamontov and Greg Diedrich

Step 1: Schematics & Shopping List

Here's the plan of how to assemble the trailer. Also included is he shopping list which is around $150. However, if you decide to skip on the paint job and advertising on the sides it can be reduced by $50. Also, some parts on the list can be scavenged, like the milk crates, buckets, hose, plywood etc. reducing the cost even more.

Step 2: Assemble Top of the Trailer (part 1)

This part holds the buckets in place.

Cut the plywood to appropriate size and drill 6 holes on each side for the threaded rod. The way we measured everything out is by placing the milk crates on the plywood, spacing them out the way we wanted them and marking the spots to drill. 

Then cut 2" by 2" into appropriate chunks and drill holes at the ends. We have 2 long ones going parallel to the plywood, then shorter ones perpendicular (so they hold the buckets in place).

Then even shorter ones on the top of threaded rods which will later hold the crates.

Step 3: Assemble Top of the Trailer (part 2)

We decided to sink the nuts into the wood on the 4 small pieces on the ends. The way you do it is by drilling a slightly larger hold on top of the one that is already there but not the whole way through, then you hammer the bolt in there and screw the whole thing on as if it was one big nut.

Use gorilla glue (or some other type of wood glue) to place medium length wood on top of the short chunks of wood that sit on the ends of the threaded rod. You could screw them in but these things are there only to prevent the crates from sliding back and forth.

Step 4: Paint the Top of the Trailer

This step is optional but it will prevent the wood from rotting and make the trailer last much longer. In this case we put on 1 coat of primer and 2 coats of medium gray paint (indoor/outdoor, high gloss, latex).

Step 5: Bend the Conduit

Cut and bend the conduit into this shape using conduit bender. The curve on the right should be about the curve of a bicycle wheel. Trace a wheel on the floor with chalk and then slowly bend the conduit until its about the right shape using the chalk outline as a guide.

Step 6: Bolt on the Parallel Metal Beam

Cut the 8020 metal to appropriate size, drill 4 holes into it and bolt it to the bottom of the trailer. Make sure there is a little bit of metal sticking out on one side, that's where the conduit is going to attach to. And, most importantly, make sure it is straight.

Step 7: Attach Conduit

Attach the conduit with 2 bolts. Remember, the shorter end is the one that is getting attached to the trailer.

Step 8: Bolt on the Axels

Place the thing Steel tube (which is going to be the axle) into the slot of 8020 metal and bolt it to the bottom of the trailer with long thin bolts. The easiest way to do it is to first drill one hole in the center straight through both the steel and 8020, bolt it on temporarily, then drill the other holes so you don't get misaligned holes. 

Step 9: Put in Pins to Hold the Wheels

Put on the wheel and mark spots on each side of it to drill. Put the pins into the resulting holds to hold the wheels in place.

Step 10: Assemble the Hitch

This is the means of attaching the trailer to your bike.

Plug the end of the conduit with a cork or a sliced up piece of hose you got. The bolt that is going to go through the conduit is going to help prevent it from going all the way in.

Then wrap a 2 foot long piece of hose around your seat post and bolt it to the end of the conduit.

Step 11: Put in the Eye Bolts

Put in the eye bolts, 3 on each side. Make sure they are in the center of each slot that holds the bucket + milk crate.

Step 12: Attach the Kick Stand

This step is pretty straightforward. Drill a hole in the plywood where you want the kickstand to go and bolt it on. We decided to put it on the side so it folds under the trailer.

Step 13: Finishing Touches

Put on the wheels. Put on, paint and stencil the side panels (optional). Get 2 foot bungees (6 of them) to hold the crates in place.