Adams trail-a-bike replacement spacer shim for hitch

A replacement Trail-a-bike hitch seatpost shim to help fix your trailer

A replacement trailer hitch shim for the Adams trail-a-bike and other trailers



We use an Adams Trail-a-bike (aka Tag along, as some people call it) to tow our child occasionally.  It is kind of like a tandem bike attachment for kids. The steel hitch slides onto a seatpost, and clamps on via 2 bolts and a hex-wrench.  The other end of the hitch has a square-shaped key and a hole for adding a retaining pin to hold the trailer in place.  There are spacers included that fit in there for different seatpost diameters.

We have a Weehoo trailer as well, and this shim should fit that hitch as well.  This may also work for other tag along bikes, like the Weeride Co-Pilot and the Kazam Co-pilot.  Both of those clamp onto the seatpost of the adult's bike.


Adams Trail-a-bike hitch
Adams Trail-a-bike hitch

We sometimes swap the trailer between bikes. Unfortunately, the bikes have different seat post diameters.  I was trying to set up for a ride the other day and could not make the Trail-a-bike hitch fit onto the seat post. None of the included spacers either, which was pretty frustrating!  I may have clamped the hitch too tightly in the past, and had bent it as a result.  The smallest spacer was too big.

Designing a new spacer for the trail-a-bike hitch

A new spacer is a simple part to design, so I made my own that you can download if you need one.  I made this for a seatpost with a 30.6mm diameter.


I'm making this available without warranty, etc. If you choose to print and use this, you accept all responsibility and liability for the use of the part!


  • Inner diameter: 34.5mm
  • Outer diameter 37.6mm
  • The file is in STL format.
Adams trail-a-bike replacement spacer shim for hitch
Adams trail-a-bike replacement spacer shim for hitch


Here is the download link.  I hope this is of use to you!

I’m trying to make it easier for families to ride bikes together by sharing experiences and developing helpful products.

Or follow along for updates:

5 thoughts on “A replacement Trail-a-bike hitch seatpost shim to help fix your trailer

  1. Reply
    Dave - July 23, 2023

    I’ve been needing a shim myself and the $50 pricetag that Adams puts on theirs is a little eyebrow raising. Your download link doesn’t work, any chance you can make it available again? Thanks.

    1. Reply
      ascentale - July 24, 2023

      Hey Dave, thanks for letting me know about this. $50 is pretty expensive for a spacer. I’ll look into the download, I think there might be some file permissions thing going on.

  2. Reply
    Jonathan - March 26, 2024

    The download link doesn’t appear to be working. Can you try fixing it or email me the STL?

    1. Reply
      ascentale - March 28, 2024

      Thanks for letting me know about that download link for the STL, Jonathan. I’m looking into this.. I will keep you updated!


      1. Reply
        ascentale - April 3, 2024

        Hey Jonathan, can you try “ordering” it from this page on my site? It is a free download:
        Let me know if that works.

Leave a Reply

Your email address will not be published. Required fields are marked *

Scroll to top
Join Waitlist We'll inform you when this is in stock. Please leave your email address below. We won't spam.