Construction of a bicycle wagon (or "The Mandt name lives on?")
I've just completed construction of a modular cargo trailer to hitch onto my bicycle. You see, I'm hoping to be able to accomplish all farm operations this year completely independent of a car or truck (or driver's license, for that matter!). So I decided I needed a larger, more practical trailer than the one I already had (which wasn't even designed for hauling cargo at all – though it's served me remarkably well!).
I was inspired by the Bamboo Bike Trailer page and associated instructions for building one, and thought, well if it's that simple, then why the heck not?
However, rather than construct one from scratch out of bamboo (which isn't even a locally-available good), I decided to make use of another even more practical, locally available good: an existing bike trailer!
See how I did it below...
 |
I began with a very barebones aluminum bike trailer that I acquired some time ago, sitting neglected on the side of the road in some Toronto neighbourhood, beside a piece of cardboard with the word "Free" written on it. It wasn't very useful because it had no real ability to contain cargo unless your cargo was a single large flat object accompanied by a host of bungee cords. |
 |
Then I cut it in half using a hacksaw. |
 |
I extended it to 64" long using hardwood (oak) dowels of just the right size that I bought at the hardware store. I doubled up the dowels for extra strength. (Note that I'm no engineer; this is all riding on "gut feeling.") |
 |
I reattached the wheel brackets and wheels. |
 |
Then I took that slab of wood that had been sitting on the original trailer, cut it into three narrower lengths using a skill saw, and cut them further to size to form cross-pieces, attached with heavy-duty galvanized strapping and bolts. I figure these would add some extra rigidity, as the wheels seemed a little "shifty" without them. |
 |
Next I undertook the magical step of adding spokes to the underside of the wagon. This idea comes from the Bamboo Bike Trailer building instructions I was referred to by the owner of carryfreedom.com. It sounds like a good idea. I attached four loops of wire rope between each of the four corners of the load bed and a floating hub I cut out of wood. I then twisted each loop several times using little bamboo sticks until it was tight and the load bed was square. It felt like a good reinforcement to me. (Granted, I don't know exactly how it reinforces the load bed. I think it keeps it from wanting to fall apart.) |
 |
The next step was to cut a piece of plywood to fit the surface of the wagon perfectly. I attached it using zip-ties. (I feel like I'm cheating with those handy little things.) I make sure to cut out little inserts in the surface for pairs of eye-bolts I fastened at three points along the body of the wagon. The eye-bolts will anchor straps used to tie down whatever cargo I'll be hauling. |
 |
I then attached rails to the sides of the wagon. These were actually constructed out of rails that came with the original bike trailer (though I forgot to photograph them). I just cut them in half and "dowelled" them similarly as I had done for the body of the wagon. |
 |
I created cross-pieces for the rails to keep them from wobbling. These I made from existing cross-pieces from my trusty old orange trailer, again giving them the dowel treatment to make them the right length. They have convenient plastic pieces on the end that securely seat bolt heads, which pass through the rails. Also pictured here are the semicircular wheel guards I built out of plywood and attached using brackets and zip-ties. I also took the trailer hitch off my old trailer and attached it to the new one. So really I'm just recycling old trailers to build a better wagon. In other words, I'm cheating. |
 |
I realized that the rails as they were wouldn't be enough to keep 18-gal Rubbermaid bins from sliding off the edge of the load bed, so I added some more plywood slabs lower down on the rails, attached with zip-ties, to keep things better contained. I also made it possible to reposition the cross-pieces to accommodate whatever kind of load I happened to be carrying. I made a couple fenders for the rear of the wheels out of a bit of duct tubing I came across, and attached them using little screws, little nails, and – you guessed it – more zip-ties. I also managed to salvage straps suitable for each of the three pairs of eye-bolts to use as tie-downs for cargo. I coated all the plywood and dowels with linseed oil to help protect them from moisture damage. |
And here is the completed trailer, attached to my recently Xtracycle-modified bicycle:
I have an ancestor, Targe Gunnarson Mandt, a Norwegian immigrant to Wisconsin, who had a certain inclination for building wagons back in the mid-1800s. In 1865 he established the Stoughton Wagon Works, a company that eventually evolved into Stoughton Trailers, Inc., which still operates today. Maybe – just maybe – I could make like good old Mandt and turn out my own little wagon-building business! At least in the off-season.
Or maybe first, I should make sure my fancy new trailer even lasts a month's use. ;-)
- paul's blog
- Login or register to post comments
Comments
Congratulations ! You now have entered the world of Engineering
Hello Paul & Congratulations.
Now with the improve 2.0 version of your trailer, you are going to be loading the wagon with even heavier items than you have in the past.
If in the past you were able to load say 100 lbs (50 Kg - for simplicity calculations), now perhaps you are able to double this? (200 Lbs, 100 Kg - remember I like to keep the math simple)
Problem is, have you upgraded your Brakes and Steering to handle the additional load?
This is where the realm of an engineer comes in, and, like the Wright Brothers, a little bit of trial, error, think what went wrong, and trial again comes to play.
Most 'Stuff' is designed to withstand Double the rating in engineering terms to be safe. This is how you may get away without having the wagon fall apart if it does not get stressed too badly. However, and this is a big BUT...
The stresses imposed by having the wagon to double it's original weight may cause Brake failure or worse yet, cause you to not stop at the bottom of a large hill, when trying to decelerate, due to the height of the hill, the force of gravity, 9.8 m/s[squared], and the weight [force of gravity acting on the mass of the contents in the wagon.
Some simple tests would be needed, but could confirm how well, or not so well, your Bike's brake system works or does not work is to measure your stopping distance with a *known* weight on the trailer hookup and a suitable slope for testing. [with appropriate foam padding around the luge posts should you decide to perform these tests yourself]
Keep up the good work - lets hope for a safe summer of green gardening
-Terrific
-Richard
Safety
Hey Richard,
Thanks for this advice; I've received similar advice from my pal Christoph. Your points are particularly valid in Nelson where there is an abundance of large hills.
I did upgrade my brakes somewhat – added a rear disc brake (the biggest disc I could get). I still have to upgrade my front brake, which apparently is even more important since that's where most braking occurs – it's just that I don't have disc brake caliper mounts on my front fork anymore. I need to do a couple modifications before I can have front disc brakes, and this stuff is expensive! But I'll get around to it before I start hauling really large loads up and down hills.
In any case, I've been riding extremely carefully coming down hills, using my brakes a lot and getting a feel for how much impact they have at different speeds. To be safe I never coast down a hill with a heavy load – always take it down slowly and safely! And I am inspecting my brakes regularly.
Happy gardening to you, too!
Modular
I forgot to mention this about the wagon's modularity: The railing piece can be removed as a unit, so the wagon is easier to store (i.e., squeeze through a doorway) or use without the railings at all (for wide loads, for instance). The wheels are also easily removable. I'm also trying to come up with a light canopy for the wagon that I'd like to be able to secure to it quickly in the event of rain.