I just finished the third iteration of a bicycle cargo trailer. I have been relying almost completely on my bicycles for commuting for the past 11 months, but it annoyed me that I needed to use one of my cars for grocery shopping.

My first two trailers were conversions of aluminum framed child carriers, I sold the last of these two years ago. For this newest version, I wanted to step out of the box a bit and go for a different design concept. I also wanted to prove that almost anyone can build a serviceable cargo trailer almost entirely of scrounged parts and materials. In fact, the only things I purchased for this project were two 10' lengths of 1/2" EMT and 5 "U" bolts in two different sizes.



The wooden frame of the cargo bed was constructed entirely from the boards taken from a discarded queen sized" box spring. I am not counting the several hand-fulls of screws, a few bolts and some paint that was living in my garage.



I built two 26" wheels on reconditioned and painted rims. The wheels are suspended by two matching front forks (obtained from the dumpster of a larger bike shop that sells a lot of suspension forks - and tosses the originals). The forks are connected at three points to the wooden cargo bed.

Uh, yeah. There are a nine reflectors on each of the wheels. If you have ever shared the roads here in Florida with the little blue haired old ladies, you will understand completely. Most of the wooden frame is painted with four coats of a green enamel exterior trim paint. The two natural wood rails a are simply protected by some clear coat polyurethane (no particular reason for this other then I like the way it looks). The forks are protected by three coats of carefully brushed on (and thinned) Rustolium paint.



So why did I use 1/2" EMT instead of the more commonly used 3/4"?? Simple, because of the three tube, truss design, the larger tubing would have been overkill. You will notice that the center tube is bent to contact the trailer at a point that is just about 5-1/2" below the level of the two outside tubes. This design really minimizes any flexing at the point where the tubes contact the cargo bed. The layering of salvaged wood is evident in this shot. Of course, commercially supplied 2"x 3" lumber would have been simpler, but that was not part of the "salvaged materials" plan.

To mate the 1/2" EMT to the larger diameter inner dimension of the fork head tubes, I found that straight sections cut from a set of old beach bars were the perfect solution. The bar sections provided a snug fit into the fork tubes, and the EMT was a great fit into the handle bar sections. All three were pinned in place via a drilled hole and some sheet metal screws on either side.



Not the best of photos, but you can see the chromed motorcycle frame clamp on the inside leg of the fork. It is secured into the third (from the front) wooden cross support via a 5" lag bolt with spacer washers.

Now for the hitch. For any bicycle trailer, a flexible hitch is very important. Not only to allow the bicycle it's full range of ridding attitudes, but also to prevent a trailer upset from taking down the bike and rider.



This hitch is a variation of the version I used for my last trailer. it offers a three axis rotation, and of course it is of the quick release design. It is designed around a compressed air, quick release fitting.

On the bike side of this assembly, the air fitting is mounted to a dolly wheel caster (with the wheel removed and saved for some other project. This method allows about a 270 degree horizontal rotation plane and about a 60 degree vertical rotation when the hitch is mounted in the seat post area of a bike. The air fitting itself provides an additional 360 degree rotational plane. Inserted into the upper tube is the male section of the quick release air fitting. Because of the bended tube design, the "upper tube" shown in this photo, is actually the lower tube where it attaches to the cargo bed.

I wanted a "clean" looking mount so it is inserted inside of the EMT tube.





It should be noted that just using the short "male" fitting portion, would be insufficient for a secure attachment to the trailer. What I did was tap the inside of the male fitting with 5/16" threads. Then I screwed a 5/16"x 4-1/2" bolt into the male fitting. After taking down the "points" of the bolt and air fitting hex heads, I slid (ah . .tapped lightly with a hammer) the bolt and fitting inside the EMT tube. Having carefully measured the dimensions, I drilled down through the tubing and tapped a screw into the flats of the internal bolt. . . it is NOT going to pull out.

Going with my "use what you have concept", I already was using the seat tube carrier rack, so I fabricated a clamp that would secure the dolly wheel assembly to the support frame of the rack, Four stainless bolts, nuts and washers took care of that job with an assist from a piece of 1/4" hard aluminum stock. The trailer design requires a center mount on the bike, although I used essentially the same type of hitch on a sidebar pulled trailer the last time around. All I did then was to fabricate a mount on the left rear wheel stays.



This photo illustrates the trailer with a 48 quart cooler mounted on the deck. This changes depending on what I need to carry, and I have occasionally used a large duffel bag mounted in front of the cooler for dry goods. I also have a super-large Rubbermaid Roughneck storage tote that fills the entire bed of the trailer,

If you have any questions, email me and I'll try to answer them DaddoCFL@Gmail.com