Burley trailer hitch, classic or alternative?
I had one of these that had, at the end of the towing arm from the trailer, a moulded plastic part that fit in the angle between the seat stay and chain stay tubes, it then had a hinged part that was tightened down onto the seat stay. It only took 30 seconds to fit or remove. Having said all this I do not know if this it the 'classic' or 'alternative' system.