Instructables
Picture of Bike Trailer -- tough and light
Instructions on how to build a tough and light bicycle trailer out of standard light gauge angle iron found at the hardware store. This design is tough, relatively light, easy to build and easy to customize.
 
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Step 1: Collect Tools

Picture of Collect Tools
Tools required for this job include --

Hammer
Chisel
Hack saw
Adjustable wrench (two)
Ratchet with 5/16 socket
Pliers
Drill with phillips bit
Tape measure
Sharpie
Combination square

If you have a circular saw, it may be easier than using the hammer and chisel. Eventually I got sick of using the hack saw and borrowed a friend's angle grinder with a cutting disk.

Step 2: Collect Materials

Picture of Collect Materials
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These photos are just to show you what the materials look like. Below is a more or less thorough bill of materials. Costs maybe $100, but well worth it as a cargo trailer at a bike shop is about $300.

6 each conduit straps, two-hole kind, sized for 1/2 inch conduit
About 19 linear feet light gauge angle stock (find at hardware store or local big box store)
4 washers, 1/2 inside diameter
38 washers, 5/16 inside diameter
8 wood screws, 1 inch long
8 bumper washers that fit the wood screws
24 bolts, 5/16 diameter by 3/4 inch long, hex head
2 bolts, 5/16 diameter by 1 1/2 inch long, hex head
24 nuts, 5/16
24 washers, split ring, to fit 5/16 bolts
3 foot 1/2 inch threaded rod
2 each 20 inch diameter wheels, plastic spokes
3 feet 1x3 nominal lumber
2 feet 2x6 nominal lumber
6 each nylon washer, 1/2 inside diameter, about 1/2 inch deep
12 feet rope, about 1/4 inch diameter
4 machine screws, no. 10 diameter by 1 1/2 inch long, phillips head
4 nuts, no. 10, with nylon locking inserts
1 caster wheel with removable wheel and ball bearings at its base
1 1/4 bolt with pin, to be used as a quick release between tongue and receiver
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juiceman742 years ago
Hi,

Did anybody try using such a trailer for hitching kids on it. .

How Safe is it compared to commercialized products? I'm offriad of of rolling over in high speed turns.

What about a canopy and seats I didn't see any instrucatables that includes those.

What about road bumps resistance, how much of a bumpy ride is it on a white dirt road?

10x, all.
O>
arcraven (author)  juiceman742 years ago
I've not trailered any kids on mine.
One problem with this design that should be fairly easy to rectify. there isn't a rotational degree of freedom about the in-plane axis; i.e. you cannot lean your bike in a turn, as required for any substantial amount of momentum. Other than that a great build. Just be careful around those bends.
arcraven (author)  fractionalphysicist5 years ago
Yes, that is a problem I'm aware of. There's been enough play in the coupler/receive for this not to be a big problem. However, I haven't had to pedal "out of the saddle" yet with the trailer (for going over hill or sprinting). I'm interested in anyone's solution, though I prefer not to have to completely redesign the connection yet again.
What about a hinge type of setup between the caster and the bike? The hinge would be at a right angle when the bike is upright, with the caster below it, so that in a turn the hinge could go up or down depending on the direction of the lean. I'm sure someone would be able to figure it out
arcraven (author)  Msaggese5 years ago
Good idea -- sketch attached, comments welcome. (no, I do not work for Perkins + Will) I'm wondering if there will be too much back and forth movement in such a design.
hinge.jpg
This is a good idea for turning with a lean.
You might catch the spokes in the rear wheel. What about another caster in line with the support arm and 90 degrees "out" from the 1st caster.
I was thinking more along the lines of the hinge being horizontal, or bent at a 90 degree angle, so that when leaning the bike right, the hinge will open downward, and when leaning left, it would close upward. This might avoid the problem of the spokes catching, but i'm not entirely sure. i'm just thinking conceptually
Exactly, That was the only problem that i could see with it. It might work
I was about to suggest some sort of universal joint near the point of attachment to the bike, myself. If you just have it attached with a bolt, the tires would drag and screech on a sharp turn, and wear out too fast.
kklaw arcraven5 years ago
How about a heavy duty spring? The connection on my store-bought trailer that our kid sits in has a simple rigid post-and-hole connection but a section of the tow bar is actually a heavy spring. It makes turning quite easy and provides much needed flexibility between bike and trailer. Just a thought.
What I did when I needed a light-duty universal joint was to take two fairly heavy threaded eye-bolts, get one red-hot with a torch so I could open it up and put the opened end through the other eye and closed it up again. Worked just fine.
Dr.Bill3 years ago
Can You Say Erector Set ?

I wonder if this can be put into a box and marketed . . . . . .
parrster3 years ago
Brilliant. I've been looking to build something like this for my son to help with his paper run. I like this design for its simplicity and ease of construction. Great job.
Databanks3 years ago
Wow, such a cheap but effective way to make a coupler. And I've no shortage of castors that have worn out their rubber wheel hanging around...
Nice idea and thanks for sharing
Most interesting! Congratulations on a sturdy and (in its neatness) visually appealing design. I wonder, have you put it to extended use yet? I suppose not, looking at the date of publication. The reason for my asking is that I think nylon washers as bushings might wear out quickly, since it is a threaded rod. Perhaps a flush one would have been better, but then, you have the trouble of holding the axle and wheels in place, of course.
arcraven (author)  rabid_engineer5 years ago
Good point. A friend recommended filling the threads with "liquid metal" (never heard of it before) and filing it smooth so that the axle doesn't wear down at those points where it touches other parts.
Your friend is probably talking about JB Weld. It's available at most auto-repair shops like Autozone. Great project!
Baronrc4 years ago
 WOW!!!!!

this is beautifull, rabid_engineer said it perfectly, "in it's neatness visually appealing"

I really wish I hadn't sold my bike, if I still had it I would go out and do this!
godspiral5 years ago
where/what are the wheels from?
arcraven (author)  godspiral5 years ago
I bought the wheels from Northern Tool. They're about 20" diameter and have built in bearings. Here's Northern Tool website --

http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_1030_1030
weblar5 years ago
I like your trailer design a lot - it does look strong and light!!

I agree with the posts regarding the "swivel-ability" of your attachment point. I've designed and built a number of bike trailers over the years, and have accomplished that "swivel-ability" by moving the attachment point for the trailer to just behind the rear wheel/tire of the bicycle using 3/4 X 3/4 square steel tubing that is also available from hardware stores and then using a second caster to allow the full range of trailer tongue motion: up and down, side to side, and rotational.

Though the current trailer I designed makes use of a push/pull golf cart that I purchased off CraigsList for the low price of $5 and a plastic tub, the trailer attachment design I suggest has held up very well all this summer over some very extended bicycle rides (one over 225 miles).

I also replaced the cheap bearingless wheels that came on the golf cart with sleeve-bearing wheels that I bought from Northern Tools - a great place to shop for wheels for projects like these.

You can see the trailer coupler I describe also posted on Instructables at http://www.instructables.com/id/Building-a-strong-flexible-bicycle-trailer-coupler/
macrumpton5 years ago
Do you think rather than cut out a notch out of the tongue if you did a single cut and bent one side up and the other down you could overlap them so you could put a bolt through both sides?
arcraven (author)  macrumpton5 years ago
Yes, I did try this when building. The angle iron is light gauge, but not light enough to do that easily (although if you cut it craftily enough, I'm sure its possible). It was easier for me to cut the notch and reinforce it with the bracing.
rowerwet5 years ago
why not use a second caster to make the second hinge axis, connect them at the axle bolt holes (one axle bolt through all 4 axle hole ears) so that one swivel plate was 90 degrees to the other. (one for pitch and one for roll) would make the tounge connection a little different, but no major changes. great design!
turning with the second attachment would stress the rear of the bike.
the axle bolt would be the joint for bike CL to trailer CL angle changes, the swivel plate attached to the frame would be the joint for bike to trailer pitch changes, and the swivel plate attached to the trailer arm would be the joint for the bike banking into turns while the trailer stayed flat.
arcraven (author)  rowerwet5 years ago
I'm experimenting with this right now and will post my pics/opinions. At first glance, seems it could work.
arcraven (author)  rowerwet5 years ago
Seriously considering doing this. Thanks.
macrumpton5 years ago
Instead of mounting the piece of wood on the frame to mount the axle on wouldn't it be easier to just drill two axle size holes in the angle iron and mount the axle directly on the frame? Then you could eliminate the wood, brackets and mounting screws. It would even lower the center of gravity a couple of inches.
light angle isn't strong enough for the 100lb limit. The wood in the middle of the platform gives it strength(making up for light angle).
arcraven (author)  ericdncn675 years ago
Exactly. Without the 2x6, the axle bends under heavy load, causing the wheels to splay out. The wood also adds rigidity to the frame so it doesn't rack.
brizzx325 years ago
Hello good Instructable, just had a question did you just use a regular bike wheel or what kind did you use and where did you get it?
arcraven (author)  brizzx325 years ago
The tires are for garden carts. I bought them at Northern Tool. Here's the link --
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_1030_1030
ksteinhoff5 years ago
goodgnus5 years ago
Reminds me of an erector set! Any bike trailer is a good bike trailer as far as I'm concerned. Props!
Very nice instructable! Nice attention to detail. I like the way you made the angle on the trailer tongue with L stock metal. It's hard to find recycled round tube with the angle you need. The name of the pin you mentioned you forgot is a clevis pin. I also like the use of that type of wheel -do you have a link for your source?
Thanks! I used Northern Tool to source the wheels. Links to home site and to 20 inch wheel.

http://www.northerntool.com/
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_1030_1030
Those "Adjustable Wrenches" are called Crescent wrenches.
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