Single Wheeled Bike Trailer

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Intro: Single Wheeled Bike Trailer

I wanted to recycle an old foldaway bike I used for an earlier recumbent project to make a one wheeled trailer. I was inspired by an earlier instructable but didn't want to do any welding, just nuts and bolts. I'm a big fan of 1/2" conduit for lots of metal projects. This project took about 2 weeks off and on. I'm going to use it when I bike around town or to the beach for the day and carry lunch, drinks, boom box, etc. It's not meant for heavy loads. That's another project for another time.

STEP 1: Modifying the Frame

Here's a shot of the under side. I cut the existing frame and modified the vertical angle of the handlebar collar to be perpendicular with the ground so it wouldn't jam up when it pivoted. Geometry is critical here.I had to used plate steel and bolts to join the frame because of no welder. I reinforced the 1/2" plywood top with sections of 1/2" conduit that where flattened and bent in my bench vise. They were secured to the frame with sheet metal screws and eye bolts. I used cap nuts to finish the connections off to look right.

STEP 2: Hitch Mechanism

Now for the hitch. I picked up some ideas from other trailer designs I found on the web and hoped my conduit would hold up. It seems to work fine. Here's the details: I used a 3/4" piece of steel plumbing pipe and 2 caps to join everything together. It was great, no excess wobble in the collar or up and down motion. Whisper quiet. The hitch resembles a triangle shape which is very ridged. 1/4" bolts everywhere. The sectioned where cut, flattened and bent in my bench vise. The edges were ground to look nice. I had to estimate the space needed for the tire and distance to the trailer.

STEP 3: Attaching to Bike

I made a flat steel bracket to bolt to frame and allow hitch to pivot up and down. It's mounted behind bike rack bolts. I wanted the hitch to be independent of any rack mounting.

STEP 4: Safety Light and Battery

I didn't want to get hit from behind by a driver that can't see me. I thought a long time on this and wanted to use a battery powered light that blinked.

THE LIGHT
I found a piece of old plumbing drain (a "T" joint) and mounted 2 small side lights and a 4" LED light I found at Harbor Freight (I love that place). It's all epoxied together and sprayed black. The drain T slides right over the seat shaft for a snug fit. There's a hole in the top for a flag staff. The wiring ends with a cigarette type connector for fast disconnect. I used a $3 blinker inline to make it flash.

THE BATTERY
I have a 12v lead acid battery from my photo flash equipment that can be recharged and is light enough to strap to the rack over the back wheel. You could probably use a bigger one.

STEP 5: Carrying Options

This little trailer is pretty versatile. I put this plastic milk crate on for size comparison. The eyelets allow you to lash about anything on it.

CAUTION: This will not hold a person. Small dog, maybe. Trip to the store, most definitely. Trip to town or the beach with food and tune, yes.

Have fun and let's see what you can build.

18 Comments

One inexpensive way to avoid kinks in pipe is to fill the pipe with tightly packed dry sand before bending. Once you have the bend desired just knock the sand out.

That is really awesome, too bad it was not featured five years ago, but never say never... ;-)

I just built one I love it!!! The thing I added to make it cool was styrafoam pipe insulation around the edge it makes it look cool and its safer.
Thanks,I like it,have fun !
I have been looking at similar projects I must say this one should have received some sort of recycling or green award. VERY NICE JOB!
Thanks, can you send me a badge?
Nice job man!
im looking at the hitch, and i like it! i see that the hitch is a ballbearing from the front fork of the bike. i think i'll do something like this, but with 2 wheels
Thanks. I've since retired this for a two wheeled version. Just too unstable on tight turns.
It looks like you used a head tube (instead of steel plumbing pipe) from a bicycle here as your horizontal pivot and welded it to the trailer. Is the steel pipe inside the head tube?
yeah it does look like a headtube
...it is...but it's vertical,not horiz...
Do you have some kind of conduit squishing tool? I see the kink in the rail going to the hitch, so I know that you didn't use a bender for that part, but you have this getting down to a flat piece of metal (very clean) wherever you put in a bolt. I haven't worked with conduit before, so I don't know. Do you put it in a vise?
Sorry for the late reply, yes, I use the vise for bending all of my conduit.
How did you flatten the ends? I'm imagining a vise and a cheater bar for more leverage or that you have access to a press.
Cool. Nice hitch.