Instructables

Bicycle cargo trailer--200 lb capacity, $30 for parts

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This bicycle trailer is made from 1/2" EMT conduit that is bent and brazed into a frame. It uses scavenged bicycle wheels, has a plywood cargo bed, and can be modified for any use easily. The frame alone weighs 15lbs, and with a hitch, plywood, and wheels it weighs 25lbs or so. It carries 200 lbs safely, and it can haul up to 450 lbs carefully.
 
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Step 1: Obtain parts and tools

Tool list
1/2" conduit bender
hack saw
tape measure
marker
punch (or nail)
hammer
vice
1/8" bit and 3/8"
drill
half round file
oxy-acetylene torch or arc welder
plentiful brass brazing rod
brazing flux. goggles, and gloves
bricks for holding frame
framing square / "L" layout tool

Finding and Buying Parts
You can find a lot of the parts, particularly if you're near a metal dumpster or a building renovation that might be ripping out conduit. Metal shops often have scraps of flat stock that you might be able to take.

Wheels: Go with what you can find. Feel lucky if you have the option of mountain bike wheels over road bike wheels. The dimensions given here are for carts with 26", 27", or 700c wheels. If you use 24" wheels, you can reduce the cart depth by 1", and if you use 20" wheels reduce the dimensions by 3" (spine and ribs dimensions). 700c and 27" wheels work, but ther're less strong, particularly laterally, which is important when you're hauling a load around corners.

Find wheels at bike shops or in the dumpsters out back. I've had good luck asking bike shops for old wheels, and in college metal recycling dumpsters. Make sure you get 2 of the same diameter, with the diameters within 1/2" or so with the tires on. You can get tubes with small punctures behind bike shops.

Another wheel possibility: It's easiest to use 2 front wheels because they will have the same hub spacing. However, you can use a front wheel and a rear wheel if you make one of the wheel wells longer and increase the hub spacing for the rear wheel to 4 3/4", instead of 4". Or measure your wheels exactly. Hardware stores carry the EMT conduit and hardware.

You will save some money if you can find scrap 3/16" by 1" bar, plywood and 3/8" ID tubing. Try metal dumpsters, scrap bins at machine shops and mechanics' garages, etc.

In the store, hardware parts are generally less expensive in the bulk bins than in pre-packaged boxes. I can't find rod end ball joints anywhere accept mail order (I've used McMaster-Carr). The shaft should be 1 1/4" or more, and have threads that are 3/8"-24 or 3/8"-16. (The 24 and 16 refer to threads per inch.) Get a nut to match the threads. The hole through the ball should be 3/8" wide. You can order it from mcmaster.com. It is part 6072K64 for the oil-impregnated bronze race with a chrome plated steel ball and right hand threads. It costs $5.92 without shipping. I think shipping is $3 or $4. You might consider getting a welding respirator ($12) from McMaster-Carr at the same time.

For plywood, ask at a lumber yard if they have scrap wood. Building renovations and construction also generate waste plywood that will work fine.

Using the tools
To use a conduit bender, line up your bend mark with the arrow on the bender. Step on the foot plate, while pushing down and pulling sideways on the handle of the bender. Bend until the bubble level reads level with no force on the handle.

Working with metal in this project is easy, but takes some practice. To cut with a hacksaw, make sure the piece is clamped well and the cut is close to the clamp. Use the full length of the blade, pushing down hard enough to cut but not hard enough to bind the blade. Use steady, even strokes pushing forward. Don't press down hard on the return stroke. Hold both the back and front of the saw.

When using files, the cutting happens on the forward stroke. Pulling back with downward pressure on the file will only dull the file.

To cut with a tube cutter, align the mark with the cutting wheel and tighten the screw just enough to score the metal all the way around the tube. Tighten a little more and continue turning the tool, ensuring that the cut is in the original groove. Continue around the tube. This tool is useful for the conduit, but a hacksaw is more reliable.

To braze with an oxy-acetylene torch, it's a good idea to get a lesson from someone who knows how. Always set the regulator carefully and keep the tanks well secured so they could not fall. Use gloves, #5 shade eye protection, and work on non-combustible surfaces. Keep fire-extinguishing paraphernalia present. Work with good ventilation, especially with galvanized conduit.

To drill into metal, make a starting dent with a punch or nail, and drill a small hole at high speed with a sharp metal bit. To enlarge it, use a lower speed and watch out for the bit catching as it breaks through the material. Always drill into material secured in a vice or by clamps.

General safety: Wear gloves when things are hot, don't wear gloves with spinning tools. Wear safety glasses when there are chips flying (drilling, cutting). Wear long non-synthetic, non-flammable clothes when working with the torch. Wear closed-toe shoes or boots. Don't breathe fumes from cutting, heating, or painting. Have fun and take care of yourself so you can ride your bike and pull your bike cart and tell your friends how great it is to not use a car.
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I made this trailer and used 10 inch hand truck wheels so only needed 4- 10' 1/2inch conduit and I welded it all together with a flux core welder

jsadler15 months ago

Material availability is more and more of an issue in the US as well. Metal electrical conduit is about the only reasonably priced metal tubing in many areas. The prices in Home Depot for a common galvanized, steel pipe make me feel like I am buying gold. Copper and brass are off the charts and aluminum is as well. We are not even seeing hardwoods in Florida at sane prices. As less people are "makers" now than in years gone by the industry is not supplying components the way they once did.

farbs7 years ago
Hi! Im 13, and I desperately want to build a trailer. The problem is, I dont own a welding gun (Mainly because im 13) but my moms boyfriend is a carpenter, and I could probably convince him he could use one. If im lucky,he might get one by christmas. Then I could get the parts and make it by Febuary. way too much work. I dont think he would let me use it anyway and its not the same watching someone else build it. So even before I saw this, I decided that I would build a cheap, no-weld trailer. Any suggestions or tips?
aaron (author)  farbs7 years ago
Yeah, check out the plans for the "bamboo trailer" from carryfreedom.com/bamboo.html You'll have to email Nick for the plans. It's a lovely design, and fairly simple. You can build it from conduit, bamboo, wood sticks or poles, (i wouldn't recommend PVC)... Good luck.
Kevvixx aaron6 years ago
If I were to use bamboo, where could I get it?
jsadler1 Kevvixx5 months ago

In many places watch Craig's List under free stuff. Many areas have bamboo in excess and home owners will be thrilled to have you cut down bamboo for free. In Florida I even see the huge timber type of bamboo offered for free. That stuff can be better than five inches in diameter and up to 90 feet tall. In the eastern nations they build large buildings out of structural bamboo. You can also use bamboo covered with fiberglass or epoxy glass for even greater strength and super long life.

Kevvixx aaron6 years ago
what is a good cheap material that I could use since you said that PVC was not a good recommendation?
camb00 Kevvixx6 years ago
copper pipe no welding just soldering but its very expensive now but would be easy to use
This is a good suggestion for ease of costruction, though it would have to be for farely light loads, copper is rather soft. PVC is very sensitive to sunlight, it will scorch and become even more brittle than it already is. Aaron's right, it's a bad choice. Threaded piping/tubing is a good idea. Preferrably aluminum, though steal would work, it'd be very heavy.
I'd say fiberglass tubing would be a good substitute for bamboo. It comes in round and square.


Better yet a person can make their own fiberglass tubes easily with either glass and polyester resin or glass and epoxy resin. Cut your shape in polystyrene insulation, which cuts easily. If using resin you must coast the polystyrene with paper as resin will melt the foam. If using epoxy simply apply the glass and work in the epoxy. Any size, shape, weight or strength can be created. If you do use epoxy you want only white paint as summer heat can turn epoxy a bit soft if painted other colors.

jsadler1 Kevvixx5 months ago

PVC can break with no warning at all. Sunlight is one PVC killer. Accumulated stress is another. Common PVC is not structural PVC. You may discover that the price of structural PVC is a bit outrageous. Simply never trust PVC.

jsadler1 farbs5 months ago

A good way to start is by using nut and bolt construction. If the trailer works well and you are satisfied tow it to a shop that has a good welder and pay him a few bucks to weld it together or simply keep an eye on your nuts and bolts as that method can make a long lasting and very repairable trailer that can be superior to welder units simply due to it being so very easy to change a worn or damaged piece.

zach911 farbs6 years ago
if you were to weld make your sure you were a helmet. the bright light could burn your retina in 15 nanoseconds. thus causing you to lose ability to see.
bumpus zach9116 years ago
"Wear" not "were" "god ppl learn English"
zach911 bumpus6 years ago
Dude its people not ppl
bumpus zach9116 years ago
Aluminum is great. I had a friend in high school who's grandpa built him a trailer using the the 'L' shaped aluminum rod(angle iron). We used it for our surf boards for years. You can use screws to bolt it together. Be sure to use lock washers/bolts. You might also consider looking at reclaiming used material, such as rods from an old patio umbrella, lounge chair, etc. Good Luck and don't stop until you've got it!
You could probably build this same trailer using brackets and pipe fittings instead of welds. Though it may not be quite as strong, it should still be rather structurally sound.
Jkeen1981 year ago
Thanks for great instructions, photos, sketches, and ideas. Just finished trailer using your plans with a few variations and it works great!
Stick welded instead of brazed, used threaded tube, lubed and backed off one turn for swivel connection to tie rod end, and 20" tires. Have less than $18.00 invested!
Thanks again!
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st_indigo2 years ago
Hey Aaron, great instructible, and good job with the documentation of the build.

I ordered a couple 14" wheels from Surplus Center with the intention of making a bike trailer and wanted to pass along the link. They have over 2000 in stock, and they are cheap, durable, and non-pnuematic.

https://www.surpluscenter.com/item.asp?item=1-2770&catname=wheels

The only issue is that they are hub-less, and would need a well-greased axle (9/16", I believe), though long bolts would probably work just fine. The design of the cart also would need to be modified for the smaller wheels.
olmon2 years ago
The neatest hitch idea I have seen yet is at this one - - http://www.instructables.com/id/Welded-bike-trailer/
These Trailers are amazing to look and very useful
co2wms7whcc3 years ago
Really, MIG welding is fairly easy to learn. Especially if you braze, because you will already have practice watching the bead.
Crashbox5 years ago
Here's a cart that started as a trash find. It was an InStep bike trailer I found in a neighbors trash. I welded in a couple of frame supports, changed the hitch, welded up the 3/4 emt tubing, added lights, works great. Crashbox. dog.house9@verizon.net
DSCI1380.jpgDSCI1379.jpg
Crashbox, I am interested to know how you built the axle assembly for this trailer. It looks awesome! I have been creating plans for a trailer like the Y-frame that Carry Freedom builds but I can't seem to figure out how best to mount the wheels without building a 'wheel well'. I like the clean looks of yours.
Eric, Attached are pictures of the wheel mounts.
DSCI1910.JPGDSCI1911.JPG
bikerusl4 years ago
I would caution people about brazing the coated or galvinized metal. That stuff is extremely toxic, you don't want to breath any chrome! Other than that this is the most professional seeming DIY trailer I've seen. Good job. I build trailers with CrMo bicyclefamily.ca
hackin5hit4 years ago
Thanks for some inspiration!!! Because of this Instructable, I made my own trailer, viewable at

http://undefined-macrolife.blogspot.com/



Thanks again, I will be making one from your design this week. I weld them, and am very much a beginner welder so the welds are ugly (getting better fast though). Anyone in the Olympia, WA area wanting one of these contact me through here or the link, I'll help you build one, it is fun.

So glad that you have this posted on instructables. I was going to make this cart a while ago and lost track of the instructions. It was the first thing that popped up when I googled EMT Bike Trailer. Thanks!

What a great project! I've just cobbled together my first trailer from bits and pieces, it pales in comparison to your professionalism.
Here are some photos. It was the hitch that flummoxed me the most.
http://picasaweb.google.co.uk/clockworkdoorbell/Trailer#
cavegit4 years ago
How do I convert my salvaged rims that I have to bolt on one-side, instead of having to bolt them on both sides of the rim? Almost completed my 2 carts with a 225lb. each weight limit. I used a frame from 2 fold out lawn chairs that I had gotten from CVS for 90% marked down price :)
cavegit cavegit4 years ago
I dont wanna spend $35 per rim for these and i need 4 total :( http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200331764_200331764
goodgnus5 years ago
Almost finished, just need a plywood bed and add some nylon washers to the hitch to stop a little rattle.
trailer.jpgtrailer7.jpg
i think there is buffer between, just steel pin contact is very hard, not comfortable with bike rider
SureShot5 years ago
This is great, thanks for an awesome instructable!!!
this is fantastic! thank you! i've been playing around with trailers for some time. i've got a shabby wooden one right now that squeaks like an old rocking chair. i haven't really tried to max it out. . . it's still needs some finishing touches. this is a great instructable! i love the pictures too! - doug from somerville
you could mount that ball joint horizontally from the plate going to the left...and inside the ball joint, you could attach another ball joing going in the same direction that you have yours already in the picture...this would allow for movement up and down and left to right...that is if you have your ball joint freely moving within the tube that is attached to the bike
my cousin made one of these but with smaller wider wheels. it worked great.
goodgnus5 years ago
You can get plans in PDF format from the original designer at http://bikecart.pedalpeople.com

Plans are very comprehensive. I built a slightly modified version of this last weekend, almost complete, very sturdy, looking forward to using it, see attached pic.

Uses 20" bmx wheels instead and moved back to aid stability, details in the PDF version.
trailer2.jpg
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