I just got a link from roots radical about some tips on connecting the chariot trailer to the xtracycle.

Anyway, I just went to the hardware store, got a long threaded rod (I think mine was about 8″ long). The diameter of the rod should be the largest that will still fit through the hole on the hitch receiver. I also picked up 2 self-locking nuts and 2 rod collars (this was the only tricky part but I just brought my X into the store so I could make sure the collar fit inside the back/bottom tube of the X), and lastly some large washers (larger than the X’s tubing). Slide the rod through the back tube, put the collars on (I kept mine as far apart as possible), slide the washers on, then slide the hitch
receiver on the left side, then the nuts on both sides. Tighten nuts until everything is snug but loose enough that the hitch can still rotate a little.
I wonder what the Xtracycle people think of this? It looks great to me and is probably what I’ll do. I did read that there is a 50 lb weight limit for the tail end of the Free Radical, so I’ll probably put my kids in the trailer, then use a small hanging scale to see how much veritcal downward weight is on the connector.
UPDATE:Here’s the Xtracycle guy’s response
Posted by: “Rick Pickett” rick.pickett@mac.com rickpickett3
Fri Feb 20, 2009 8:38 pm (PST)
called out weight limitations on your FreeRadical sticker/handbook,
then you should be fine. We notice cracking near the dropout when
people overload cargo on the tail, but that’s usually on day-in/day-
out trekkers who are touring non-stop and/or are generally hard on
their equipment.
Rick
SECOND UPDATE: a couple more pictures

On the hitch side, I only use the nylok nut to keep it on. no washers on this side of the xtracycle.

On the right side of the xtracycle, i have a large washer with another nylok nut.
On the inside, i coudln’t find any of wes’s aforementioned “2 self-locking nuts and 2 rod collars”, so I used some regular nuts and smaller washers that fit the inside diameter of the rear-tube. Hope this helps!
This looks like the best DIY option I’ve seen. I still owe you some pictures of my less-than-ideal Burley trailer setup with my Xtracycle…good luck!
I love the mud flap. That thing could stop a large rock.