It worked brilliantly on a 531 frame with Campag seat post and on a couple of carbon fibre framed mountain bikes for all the years I needed it and much the same without any failures using a Cresswell U+2 tandem child cycle trailer after that too, so I suspect other issues were at play with your bikes.
I would highly recommend either of these child trailer solutions and the Cannondale is a hardshell plastic base with a lightweight rain canopy so it was very robust too.
I would highly recommend either of these child trailer solutions and the Cannondale is a hardshell plastic base with a lightweight rain canopy so it was very robust too.
