Race Car Bike Trailer

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About: I got an old sewing machine when I was just a kid, and I've been hooked on making stuff ever since. My name is Sam and I'm a community manager here at Instructables.

Intro: Race Car Bike Trailer

This is a race car-inspired bicycle trailer I made for my 2-year-old from parts of an old jogging stroller, a 55 gallon plastic barrel, some scrap wood, and a few other odds and ends.

It's fairly lightweight, and as a neighbor put it, "looks bad as hell." (Not my line, but I agree!)

It took a few months to complete, working on and off. It was painted to match an old 10-speed that I restored for my wife, and has upholstered seats, covered wheels, and a trunk to carry lunch for the family.

This open-top design works well for the age of my child, but the techniques I used to make this could be applied to make a similar child trailer in almost any form, such as to accommodate a sleeping baby, or to included some kind of canopy, for example.

Thanks for taking a look . . . and as always, let me know what you think!

Step 1: Old Jogging Stroller

I had to scour my local thrift stores for many months before I found an ideal jogging stroller for this project. I picked it up for only $5 and everything was still in great condition, including the tires. It was almost a shame to take it all apart! 

The rear wheels are attached to a flat piece of metal that is bolted to the stroller frame. This wheel assembly worked out perfectly for what I needed, as did the handlebars which were modified to use as the tow bar. 

Step 2: Trailer Layout

The finished trailer pod (not including wheels or tow bar) is 36" long, 17" wide, and 12 1/2" at the highest point. The opening is about 12" by 15".

I laid out the side profile on 1/4" plywood and cut out two matching pieces with a jigsaw. The bottom board that creates the base of the trailer is 16 1/2" wide and 30" long, and was made from 1/2" plywood.

I wanted the trailer to invoke thoughts of a classic race car. As I was drawing it out and working on the details, I was tempted to omit the curved trunk area to simplify the build, but I'm glad I didn't as I think this really makes the whole thing come together.

Step 3: Body Build

To build the body, I began by cutting a small stack of 3/4" strips of 3/4" plywood. These became the framework of the body that was then covered with panels of 1/4" plywood. Everything was glued together with wood glue and fastened with finish nails.

Everything was measured, cut, and custom fit as I went along, although there was quite a bit of trial and error involved. This same basic building method could be used to make any number of shapes or styles. The trick is to make sure everything is square, well-supported, and not overbuilt (so as to keep the weight down).

Step 4: Trunk Lid

The lid to the trunk proved a little tricky, but not as bad as I had expected. 

I cut four individual curved pieces that matched the profile of the side of the pod with my scrollsaw, and used these to create a frame to which I attached a piece of 3/16" hardboard (like masonite). This was all held together with glue and lots of clamps.

Step 5: Tow Bar Anchors

Because of the narrow width of the trailer, I had to have the tow bar attached about 4" outside to the left of the trailer in order to have enough turning clearance for the rear bike tire.

The towing aspect of this project took a lot of work, and I studied many options before I settled on this one. I made two brackets from solid birch that were glued and screwed through the sidewall to additional support pieces made from 3/4" plywood on the inside of the pod.

Two long bolts extend through the brackets to securely fasten the tow bar.

Step 6: Hitch

The hitch was made from a 4" eye bolt, threaded and epoxied into a piece of dowel that is bolted to the tow bar.

The receiver end of the hitch (on the bike) is made from a piece of square tubing that was cut, drilled and shaped, before being bolted the rear axle of the bike.

A hitch pin was made with various pieces of hardware that I found around my garage. One of the main pieces of the hitch setup is a rubber grommet that fits into the eye bolt. I had to trim down the top lip of it a little bit with a utility knife so I could squeeze it into the eye, but it fits in there nice and snug. This grommet eliminates any play in the hitch, but is flexible enough to allow the trailer to pivot in all directions.

I'm curious to see how this hitch setup holds up over time. To be extra cautious I have a safety strap in place as a backup if anything happens to fail, which I cover in a later step.

Step 7: Wheels

The wheel assembly was attached with 1/4" bolts through the bottom of the trailer into the trunk area.

Step 8: Trunk

The trunk lid was attached with some old dark-colored hinges I had in my junk drawer.

A finger hole was drilled in the back of the trunk lid to open and close the trunk.

Step 9: Wheel Covers

The wheel covers were made from the bottom of an old 55 gallon plastic barrel. These shapes were cut out using a jigsaw and attached with 1/4" bolts, along with some nylon spacers.

Using power tools on non-flat surfaces is a little risky. If you ever do something like this, work slow and support the work piece as much as possible.

Step 10: Seat

The seat pieces were made from 1/2" plywood, foam, and vinyl fabric. This was my first real attempt at upholstery, and it's harder than it looks! I was okay with how they turned out, but I'm sure many people could do a much better job.

A seat belt was made with 3/4" webbing and a plastic buckle. The seat bottom was screwed in place from the underside of the pod, and the seat back was screwed in place from inside the trunk area.

Step 11: Safety Strap

A safety strap was made from 3/4" webbing and a plastic buckle. This was attached to the tow bar through the bolts that attach it to the pod, and the bolt that holds the hitch in place.

The holes in the webbing for the bolts were created by poking a soldering iron tip through the webbing into a hole drilled into a block of wood. Some zip ties were used to hold the webbing in place along the bar and keep it from flapping around.

Step 12: Rear Reflector

A rear reflector was bolted in place on the back of the trailer.

Step 13: Paint Body

Once I had all the pieces put together, I disassembled the entire thing to paint it.

I brush painted the interior brown and the trunk area black.

I wanted the exterior to be super durable, so I brush painted it with three coats of Rustoleum hunter green oil enamel. I waited for a couple of days for it to dry completely, and then sanded it smooth with 220 grit sandpaper. A final coat was applied with the spray can version of the same color. This gave it a nice, smooth finish.

Step 14: Paint Stripes

I masked off and covered the body so I could add some white stripes. The trick is to paint a first coating in the existing color (in this case green) all along the taped edges, before painting the top color (white). Any bleed-under that occurs only does so with the first top coat, but it matches the base coat so therefore and goes unnoticed. Additional coatings then leave nice clean lines between the contrasting colors once the tape is removed.

I waited 24 hours after the final green base coat before I taped for the stripes. I applied the tape-sealing coat of green, then three light coats of white spray paint, waiting about 10 minutes between each coat. I waited 20 minutes after the final coat before removing all the tape and newspaper.

Step 15: Finish Details

Final details were added with brush-on black paint. I let the entire thing sit for about 24 hours before I reassembled it. 

A few little blemishes here and there were touched up as I waited.

Step 16: Reassemble and Ride!

That's it! Thanks for looking.

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49 Discussions

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imhhawk

2 years ago

Awesome build. I think it would be cool to build it as a three wheel pedal car instead of a trailer.

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MeanUncleBob

2 years ago on Step 16

Ahhhh, meals on wheels.

Kinda funny I did the same eye bolt and dowel as a connector. Used an old hunk of runner/mat as a buffer.

Got a few ideas so may build a cargo trailer from mine.

thanks

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Databanks

3 years ago on Introduction

Very nice. I'm having some thoughts on the towing design - Rather than pivot at the bike axle, would it be better to run a bar from each side of the back bike wheel and make a hitch there or do you have plenty of clearance in the existing design?

Also, I'm wondering if you could use some of the plastic drum on the trunk lid to save the time spent curving the ply. Just coming up with ideas - your design looks bloody brilliant

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bwh13

5 years ago

Clever build!

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infernisdiem

5 years ago on Introduction

I saw this and thought that it was an old kid's trailer converted into a car, I love this, I am kinda waiting for my son to out grow his bike trailer so that I (or my father who is better at wood working) can make something like this out of the frame :D

Very cool project; one that I'm definitely going to have to try, but I do have a safety concern I'd like to hear your thoughts on:
I like the idea of a safety backup for the hitch, but I'd be concerned that, in the unlikely event that the primary hitch failed, the safety strap would pendulum the end of the hitch right into your spokes. Probably just an academic concern, as I have a hard time imagining the hitch failing to begin with.

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I guess it could happen. But I'd still want my kid attached to my bike somehow, rather than not at all. I'd like to think most people would notice really quickly if the trailer hitch broke. Before every ride, you would want to inspect the hitch to make sure it's secure and not wearing down anywhere.

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seamsterseamster

Reply 5 years ago on Introduction

Another thought, all commercial kid trailers have a similar safety strap. So they're obviously worth having, despite any possible risk in the scenario you describe.

Hope you make one! Do an instructable if you do. Love the manly beard. I can't manage more than so patchy scruff. Very jealous.

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Don't be too jealous; the testosterone that gave me my beard is the same testosterone that caused me to start balding at 17.

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I likewise started going bald in high school. So, so sad.

The trick to overcoming baldness is a hot wife that doesn't care and a nice hat. At least that worked for me.

The style does look a little like old race cars, but I thought it looked more like a nice sidecar, only it's a trailer. I like it.

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I think you're right, it does look like a sidecar. My racecar inspiration may have just been with the paint job!

You are right on with your other comment about low center of gravity and tongue length. These two concerns dictated where I placed the wheels and the seat. I put the wheels further toward the back with the seat in front of them and as low as possible, which makes the trailer stable and keeps the weight on the hitch. I made the tongue just long enough to clear the rear tire plus a couple inches, with enough room for right and left swing.

That's impressive. The thing to aim for with trailers is a low center of gravity, and balanced load over the wheel axle. The longer the trailer tongue, the more stable it will likely be, but it can be a problem as the trailer "cheats" when cornering around obstacles like poles or pedestrians. I like your idea of the wooden car body. I think I'll do a much simpler version, aiming for a Jeep body style, built on an existing kid-trailer.

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earlyflyer

5 years ago on Introduction

Very excellent project. Reminds me of an MG TD. As usual, your craftsmanship and creativity are top notch. Seeing fenders in the base of a plastic barrel speaks to your resourcefulness. Keep 'em coming!

You should add one of those little horns with the squeezy bulb thing for your son to have fun with. Or maybe mom would nix that idea?

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seamsterearlyflyer

Reply 5 years ago on Introduction

Thanks!

We thought about extras like a horn, lights, and faux gauges and such on the dash, but in the end nixed all of these ideas just for simplicity's sake.

As I was laying out the shape I wanted for this, I think I was vaguely conjuring up images of the Aston Martin DBR1, but I never took the time to look up any photos for reference. I've always liked green British roadsters, so you're right in the ballpark with the MG. Nice call!