If you are refering to the coal cart trailer, it uses a trailer arm made of steel counduit with an airline quick connect welded to it. I have a welded castor wheel bracket/airline quick connect hitch I made that strappes onto the bike.

I need to get some new pictures up. The "lid" is complete now.

If you ever want to build a homemade trailer here is how not to do it-

• Weld a steel frame capable of holding 10x the weight the trailer will ever actually see.

• Build a trailer body out of oak lumber reclaimed from old pallets. [oak is very heavy]

• Use your background in composites fabrication to make a nice light weight pine and fiberglass lid -then- quite literally, glue rocks to it.

I think this coal cart trailer give Billy-the-(lead filled)-Boombox a run for his money as heaviest trailer.