Gene's DIY
Bicycle Trailer

Gene Williams
Sacramento, California
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Bike Trailer Design Thoughts

This trailer is based directly on Mark Rehder's design as seen on his website: http://drumbent.com/trailer.html.
His instructions and photos are excellent.
Thank you Mark.
I also took some time to study the Bamboo Bicycle Trailer featured on the Carry Freedom site: www.carryfreedom.com/bamboo.html. The Bamboo Bicycle Trailer is, by far, the easiest to build and offers great flexibility of size and shape. It has, for me, a major drawback in that all loads are carried above the axles.
I went with Mark's design because it allowed me to suspend the "floor", and therefore heavy loads, below the axles making the trailer very stable in turns and on rough roads.
I've made a few changes to meet my needs and use it regularly for transporting everything from groceries to furniture. I towed just over 100 pounds about six miles. The trailer was stable and cooperative but it was a tough pull going uphill. I plan ahead now and keep the load under 50 pounds.
I went to larger, 26 inch, wheels for an easier tow on rough road surfaces and added a "floor" for carrying bulky items without my Rubermaid bin. I increased the tongue length. This has the advantage of decreasing the weight load on the bicycle and allowing me to carry longer items, like lumber. The disadvantage is a longer vehicle, which can be a nuisance when sharp turns are needed.
Enough talk, here are the pictures.

Conduit Bending

I bought a conduit bender at a yard sale for $5 and found instructions for using it on the internet. I expected to have a lot of trouble with this, however, it proved to be the easiest part of the project.

I followed the instructions and was very happy with the result of my first attempt. It took about 15 minutes due to my inexperience.

Frame Parts

Here's the basic frame before actual assembly. You can see the conduit connector and dowel used to strengthen the connection.

The Frame

Here's the assembled frame. I had to straighten the tongue to 45 degrees later to give me a bit more length and align the trailer behind the bike.

Axel Plates

After making a set of axel plates using Mark's instructions, I was unable to get the wheels aligned. While this was my fault for not mounting the plates accurately enough, I altered the plate design a bit. I made one plate with a vertical slot as Mark described, but made the mating plate with a horizontal slot as you can see.

Axel Plates Installed

Here are my axel plates as they are installed. Once mounted on the frame, I can adjust both vertical and horizontal alignment, thus making up for minor errors in construction. This proved to be of additional help later. I found that when towing the unloaded trailer on rough roads, it tended to bounce more than I liked. This was cured by tipping the tops of wheels slightly inward.

Basic Trailer

This is a basic Mark Rehder trailer before adding personal touches. It took me a weekend to get this far, but that was mostly parts search, then sit and think time to learn the techinques of building this trailer. The wheels ($5) came from a yard sale and are in great condition. New tubes and Tires ($30) from Walmart. Most everything else came from Home Depot or my nuts & bolts jar (about $25).

The Trailer Hitch

The trailer part of the hitch is identical to Mark's and the hitch described in the Bamboo Bicycle Trailer featured on the Carry Freedom website.

The bicycle part of the hitch is my own design. I was not comfortable using the thin, quick-disconnect axle skewers to support the loads I expected to carry. I came up with a steel strap bolted directly to the frame. Working with my shop vise and a hammer, it took three tries to give me something I was satified with.

It takes only a few seconds to connect this hitch. Just align the hitch with the strap on the bike, insert the pin and snap the lock-wire in place.
The pin is the kind used to connect to a tractor PTO (Power-Take-Off)

The Floor

The plywood floor is suspended below the frame on steel straps attached to pipe hangers around the frame.
No holes in the basic frame are needed. I didn't want to drill any unnecessary holes in the conduit that might weaken the frame.

The bare trailer is ready to go. It tows very easily, but bounces a bit to much on rough road surfaces. Tipping the wheels slightly inward has cured this.
My lockable Rubbermaid storage bin hasn't arrived yet.

Locks

I picked this Rubbermaid storage bin because of it's size (not too large), it's sturdy construction, and it's ability to accept my padlocks. (It's a shame it has to be that way, but there we are.)
The front locking cable serves double duty. It slips forward on the trailer tongue and connects with my bike locking system.

In Service

I brought home my first load of lumber. Home Depot is about three miles away and I spent more time answering questions from curious onlookers than delivering the load.

My bicycle is now my primary transportation. I reserve use of the car for long distances, passengers, and very large loads (appliances, plywood sheets and the like).
Carrying small furniture is a joy. I can disconnect the trailer and use it as a cart to deliver to the door.
I've had to fill the gas tank in my car only twice in six months. In that six months, this trailer has paid for itself several times over and helps give me the excercise I greatly need.

This is a 71-pound load on it's way to the recycle center. I had to gear down some to get it up a gentle hill, otherwise, easy to pull.

More on the Trailer Hitch

I've been told that I wasn't clear enough about the hitch so here are a few more detailed photos. The bike part of the hitch looks like this before mounting on the bike. Holes must be drilled to match the frame.

This is how it went on my bike. I put the "U-bolts" in place on the frame, held the strap in the desired position and marked where the holes needed to be, then drilled the strap. The "U-bolts" are actually large cable clamps that just fit the tubes on my frame.

The trailer part of the hitch is a universal joint made by bending 1 inch wide by 1/8 inch thick galvanized steel strap into two u-shapes. Then drilling and bolting them back-to-back. I placed a Teflon washer between the U-shapes to ease friction and squeeaks. The nut is a fiber type lock nut. You don't want this thing coming apart while you're on the road. I made the piece that fits over the conduit trailer tongue a little longer, about two inches, so that I could make the hole in the tongue a bit further from the end of the conduit.

Here's another view of the universal joint showing where all five holes must be drilled.

My favorite part of this hitch is the connection pin. It's a 3/8 inch power take-off pin available in any hardware store. It has a spring locking wire that snaps over the end of the pin to hold it in place.

Here's the pin with the locking wire in place.

Now to Hitch up the Trailer

It takes about five seconds to connect the trailer when I want to us it, and the same to un-hitch it.
Just align the hitch with the strap on the bike.

Slide the pin through both parts capturing the strap between the arms of the universal joint.

When the pin is all the way in, snap the locking wire on the end of the pin as shown here and you're ready to ride.
MAKE SURE THAT THE LOCKING WIRE GOES UNDER THE HITCH, NOT ABOVE. If it goes on top of the hitch it can catch in, and lock the u-joint while you're in a turn and do unspeakably ugly things to your travel plans.