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.  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.


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.

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