Two Wheel trailers

 Camper Trailers

 Trailer manufacturers

One Wheel Trailers

Advantage :

- slim / slenderly build

- pretty stabile, sometimes it needs a little weight inside to prevent bumping

- most of the times not wider than the bike

- most of the time less expensive...just one tire to replace if broken...duhhh

- last but not least...the kind of coupler..with the so called tractorcoupler it's considered by law that the trailer is actually a third wheel on the bike, which means that there's no speedlimit in contrast of rinding solo.
With a coupling (ball coupler)which is considered by law as detachable, your speedlimit is lowered to 80km/h.

Disadvantage :

- less load capacity

enkelwiel kruiskoppeling



Some nice examples are :

PAV aanhanger
The well known PAV One Wheel trailer from the Czech Republic

the very well known, nowadays made by Schuring Freebird.

One Wheel
One Wheel, American made. Imported by Schuring.

Unigo trailers
Unigo trailers

More one wheeled
More one wheeled trailers

For more kinds of One Wheel trailers I'd like te refer to the manufacturer link.