Utility Cycling - I need help building my new trailer

Next year at school I will be with out a car and I want to build a trailer for my bike, this will be my first trailer. It will primarily be used to get boxes of food and to move projects to and from school, but also be able to handle the occasional ride across town to get building supplies like 4x 8 sheets of plywood and 2x4s. I have access to a tig welder and plan on using either 4130 cro-moor 304 stainless steel ¾ thin wall tube. I thought a trailer with 20 inch wheels and a 2’ x4’ frame size would fit my requirements. I would appreciate any input on design considerations, or any thing an inexperienced tower should know. Also what are the best types of hitches, a yoke hitch that mounts to the axel or behind it in my horizontal dropouts (like on a bob) or one that mounts to the left seat/chain stay (like a Bikes At Work)

Just do a search and you'll find a few that people have built ( including myself ) but it can get addictive :lol:

...I have access to a tig welder and plan on using either 4130 cro-moor 304 stainless steel ¾ thin wall tube....
I don't know about TIG much,,,,, but with MIG or torch, regular cro-mo (4130) steel is much easier to cut and weld than stainless is. With many stainless alloys, the only practical way to make decent controlled cuts in the stuff is with a plasma cutter.
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I'd go with 4130, 20" wheels would be fine provided thy're up to the max weight you intend carrying.

How will you carry 4 x 8 sheets on a 2 x 4 trailer? I think that's a little ambitious.

TIG is fine if you're skilled, synergic pulsed MIG is better (best IMO), regular old MIG is ok depending how thin the material is.

Since you're looking at carrying potentially heavy loads you need to consider dynamic stability very carefully in your design.

There's a number of popular hitch designs out there, many of which rely on a spring or flexible rubber type connection. I'm not a big fan of those and prefer the rigidity of something like a tie rod end or cardan joint. Rigidity = stability with heavy loads.

If I need a light-duty trailer, I'll buy the $100 kiddy trailer at Wal-Mart.
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If I had to come up with a heavy-duty trailer, I wouldn't build much of anything--I'd get a heavy-duty garden wagon like this one:
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200311443_200311443
and make a reach-around handle for it, and be done with it.

You couldn't build anything like this for what price it sells at--and for hauling heavy loads, it's got a few big advantages over a "typical" 2-bicycle-wheel trailer. It's steel mesh all around, so you can tie onto it anywhere you need to. The sides flip down or remove completely. With the sides out of the way, the smaller wheels (underneath!) don't interfere with strapping BIG loads to the bed.

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As for 4x8 sheets of plywood, it would certainly hold the weight, but 4x8 sheets are still a pretty bulky thing to be hauling on a bike trailer of any kind. You'd want a long drawbar or handle, at least 5 or 6 feet long.
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There's a number of popular hitch designs out there, many of which rely on a spring or flexible rubber type connection. I'm not a big fan of those and prefer the rigidity of something like a tie rod end or cardan joint. Rigidity = stability with heavy loads.

-a million on the spring connection. They suck so bad. Our Burley(rigid hitch) got stolen and I replaced it with a kidaroo or something. The new one has the spring and it really makes it harder to pedal, it feels so bouncy and slows me down so much.

here's plans for a DIY trailer (http://www.instructables.com/id/ENK7HBIQG6EP286RJK/?ALLSTEPS) I was starting to build, but then I found one at a rummage sale for $25.

This trailer can be built with hand tools and salvaged materials
for a crazy low dollar amount. I built , and still use, this trailer
in the 1970's and have hauled over 300# with no problems.

I modifed the trailers materials to make it much stronger than
all plywood could ever be.

Salvage a clean shipping skid of OAK to cut up for ALL of the
framing members.

Salvage the plywood used for decking from a roofing job
(Don't use OSB chip board here. Plywood or forget it)

Run a metal condit brace from each front frame corner to the center of
the towing tongue.

Change the wheels to 20" for stength of the smaller wheel.(make tongue
height just a bit higher to compensate for wheel size change.)

http://www.motherearthnews.com/DIY/1981-07-01/Dime-on-the-Dollar-Bicycle-Trailer.aspx

Then there's the carryfreedom.com bamboo trailer. It is designed to be constructed from any readily available material. It can be made from steel conduit, PVC pipe, angle iron, wood, or the classic bamboo which is my choice due to the strength vs weight, and renewable/sustainable aspects. It requires no tube bending, braising or welding and no real carpentry skills, all of which I lack.

http://www.carryfreedom.com/bamboo.html#2


This one's kind of a hoot. The builder, an Aussie guy, says it doesn't make right turns very well. Wonder why? :rolleyes:

47768

I'd suggest using 26" wheels, and placing the bed of the trailer below the axles for exceptional stability.