I have Trek mountain train tagalong that I am trying to use with a 30.9 seatpost, but the clamp is too small. Anyone know if they do a clamp specifically for bigger posts?

Anyone got a number for Trek or a dealer who knows a lot about them? Cheers

The clamps come with 3 plastic shims for doing different sized seatposts, one will fit a 30.9.

Trek are on: 01908 282626, they won’t sell direct though.

I am sure I have 3 shims I must be using them wrong, anyone know exactly how the clamp assembly should work?. Cheers