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I am a technology education major who has to carry heaps of tools and materials with me quite often. I live off campus and ride my bike as I don't drive. I was thinking of jury-rigging one of those collapsible cargo wagons to my bike for transporting my 40 pound toolbox and my regular school bag. Has anyone had experience with doing something like this?? Any help is appreciated.

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    Do you have please a picture or link ? in order to better understand what you mean by "collapsable cargo wagons". – Ced May 8 '19 at 13:34
  • Welcome to bicycles Stack Exchange. FYI 'has anyone done ...?' type questions don't work very well here, you may get a better response if you re-write it to ask what approaches there are to a low cost bike trailer for they type of load you need to carry. – Argenti Apparatus May 8 '19 at 14:41
  • I also don't understand what you mean by "collapsible cargo wagon". – David Richerby May 10 '19 at 8:41
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Years ago I made a side car for my BMX bike. The side car clamped to the bike at three points with a rigid connection. Three wheel skids were cool.
Not the same thing as pulling a wagon but that's all I have :)

As Ced commented, it would be good to have a picture of the wagon you want to tow.

The first place I go to get ideas is Google images for bicycle tow bar.

I was surprised at how many results there were.

Here are some options I saw for connecting a tow bar to a bicycle

  • Seat post (this is the easiest to make and install - if it works)
  • Chain stays (solid, low center of gravity connection)
  • Fender mounting point(s) (seems like a lot of stress on a fender mount)
  • Axle (bolting to a solid axle, if the axle is long enough might be OK. I may be over cautious but using a quick release skewer makes me nervous)

After looking at the options (more detailed descriptions below) here's what I'd do:
For very little money make a prototype similar to The Dumb Stick (linked below).

  • Buy a three foot long two inch diameter PVC pipe
  • Drill a hole in one end large enough for your seat tube
  • Drill a hole in the other end for an eye bolt with a carabiner
  • Install the tow bar, hook up your wagon and experiment

My biggest concern is with stopping, especially if you are going down hill. Start small and work your way up.

If the seat post connection fails my fall back would be a chain stay connection. I had a child trailer with a chain stay clamping system that worked OK. Pulling 50 pounds of kids is a lot of work and put a lot of stress on brakes.

Seat Post The Dumb Stick (not an endorsement, just as an example)
enter image description here
Is it just me or is his seat too low?

Something like this would be easy enough to make. I'd go with steel or aluminum over "poly" if this solution went past the prototype stage.

Thoughts:

  • At rest all the weight would be resting on the wagon wheels (assuming it has four wheels, or even three). It's important that the tow bar only have horizontal stress, not vertical.
  • I get how something like the Dumb Stick pulls a kayak or wagon.
  • But what happens when it stops? Won't the wagon want to keep going and make the stick swing out to the right or left?
    I found a video of a guy who built something like the Dumb Stick and pulled his kayak around Florida. The video was painful to watch (it was too long and badly shot) but the tow bar seemed to work fine. He didn't go very fast and the roads were very, very flat.

Many of the images that come up in search look a lot like the Dumb Stick. There seems to be a lot of kayak and canoe towing going on.

Chain Stay Another option for attaching a tow bar is to connect to the non chain side of the chain stay. This is a more complicated method of attaching to the bicycle because it will require some kind of firm yet flexible attachment.
enter image description here
They are clamping to the frame and the axle. Some rigs only clamp to the frame. This looks solid but I hate clamping things to my frame.

Fender Mounting Point Some DIYers attach the tow bar to a fender mounting point. I'm very uncomfortable with this option. I don't think bicycle fender mounting points are designed to handle the kind of stress we are talking about.

Rear Axle Another option I see out there is to attach a hitch to the rear axle.
enter image description here
Call me paranoid but I would not do this to my bike.
Think this wheel should have a few more spokes to pull a load?

I'm looking forward to seeing other suggestions.

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    "Is it just me or is his seat too low?" Everyone's seat is too low, pretty much. – David Richerby May 8 '19 at 17:58
  • That Kayak arrangement is far from ideal. AT 20Kg fort he kayak, there is around 10kg hanging a long way off the back of the bike, levering the seat post. Much better would be have the wheels move midships under the yak. – mattnz May 9 '19 at 1:23
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You don't need to actually jury rig a bike cargo trailer as there a many complete trailers available commercially.

If you are looking to build something custom or inexpensive, there are parts kits available which include hitches and wheels to be used with a home-built trailer body.

Cargo wagons with small plastic wheels designed to be pulled by hand will not work very well with a bike. You need larger diameter, stronger wheels with proper bearings to handle the higher speeds.

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