Building a strong flexible bicycle trailer coupler.

Step 3 Attach trailer swivel to bicycle trailer.

Now you need to attach the coupler to your trailer. Here you are going to have to be "inventive" and consider the design and geometry of your trailer tongue. My trailer, constructed from the frame of a push-pull golf cart, consisted of 3/4" X 3/4" square tubing (similar to the attachment point I fabricated for my bicycle). I needed the rotational ability of the second coupler in order that the trailer could turn on its "third plane" - to be able to rotate (tip) from side to side - but decided that I didn't want the trailer to be able to turn left to right from a second joint in the coupler.

So when I attached this second caster to the handle of my bike trailer, I used the wheel frame of the caster wheel to straddle the tongue of my bicycle trailer, cutting the caster wheel with a Dremel tool cutoff wheel to fill the gap between the width of the trailer tongue and the bolt hole in the caster frame for the caster wheel. Although I filled this gap tightly with the cut caster wheel and it was probably sufficiently "friction fit", I did not want to take a chance with the wheel slipping off the trailer tongue so I also drilled this second caster wheel and bolted it to the trailer tongue (you can see the bolt hole in some of the pictures of the caster wheels - I drilled a hole through the wheel in the diameter of the bolt, but then use a larger drill bit to countersink the bolt head into the wheel).

Comments

[bikerusl]

At this point you might as well go for something purpose built that will be cheaper and less work: http://www.midwestcontrol.com/catdisplay_short.php?pg=119 Use 12mm or 0.5" for heavy duty trailers (>300lbs) and you could use smaller like M10 for a more average 200lb trailer. The only problem with midwest is you have to buy bulk.

Center for Appropriate Transport Eugene has these kind of hitches http://hpm.catoregon.org Also if you are in Vancouver, BC I just boult 15 of them and I don't need that many so I could sell a few to anyone interested at cost - or I am going to make a kit like HPM CAT has which has some pre-made parts (less DIY) bicyclefamily.ca

[weblar]

Of course the problem is that you have to buy bulk........ The purpose of this website is to assist people to build what it is they need for themselves without relying on the market to "purpose build" what commercial interests decide they can sell to you for a profit. My purpose in offering my ideas and publishing these plans is to allow others who don't want to buy this item in bulk to build a perfectly acceptable alternative at a greatly reduced price. I paid less than US $25 for the parts constituting this coupler and got a much more satisfactory result than the products for which my local bicycle shop charges twice as much.

[Tinworm]

very clever indeed! :)