Hey, I got my Instep Pathfinder Pedal Trailer bike off Craigslist, mine was missing the same part. I got a new coupling thru WeeRide.com, it's NOT the same bike ( their's is the Wee ride Co-pilot or Pro-Pilot) but if all you need is the part that attaches to the seat post of the adult bike, I got mine today it fits and WORKS GREAT. There number is 1.800.245.3125, tell them you need an extra hitch for the WeeRide Co-Pilot model #56455
. It cost me $10 plus S&H Good luck!
Last edited by Tiffany6477; 08-03-13 at 10:38 PM.