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  3. Thru Axle, Non Drive Side, Loose

Thru Axle, Non Drive Side, Loose

After installing your thru axle bicycle on the Neo or Neo 2 with the Tacx thru axle adapter, the non drive side is not snug against the bicycle frame and there is noticeable side to side movement.

Video demonstrating the side to side play with Neo / Neo 2 thru axle
Video Credit: Darren Ward

Root Cause

When installing your thru axle bicycle on a Tacx Neo or Neo 2 smart trainer, you must use the Tacx thru axle adapter. For the non drive side, Tacx provides two inserts with the adapter: a flat insert, and a conical insert to match your bicycle frame. If the insert is too long for your bike frame, it will “bottom out” on the non drive side when tightening the QR skewer before your frame is pulled tight against the insert face. The result is side to side play.

Thru axle inserts. Left: conical, Right: flat.
The inserts are approximately 3mm too long for some bicycle frames.

Steps to Resolve

First, ensure that you are using the appropriate insert. If your bicycle frame has a flat thru axle hole, use the flat adapter. If your bicycle frame has a beveled axle hole, use the conical adapter. If you are certain you’re using the correct adapter, you will need to contact Tacx support to receive a replacement insert.

Contact Tacx support and explain that this is the issue you are experiencing. Tacx have shipped a shorter version of the insert to owners who are experiencing this issue. The part number for the shorter insert is S0051 and its part description is “Tapered Thru Axle Insert”.

Left: original conical adapter
Right: shortened adapter provided by Tacx

Common Frames With This Issue

  • Specialized Tarmac
  • Specialized Roubaix
  • Giant TCR Advanced Disc

Additional Information

If you are the DIY type, you have options. You can shorten the inserts manually by 3 to 4 millimeters, but you can also increase the depth of the non drive side 142mm threaded insert by drilling an additional 3 – 4mm deep with a 12mm drill bit. Take special care not to damage the threads in your vice or drill press, and do not go any deeper than 4mm.

Updated on January 19, 2020

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  1. I cannot calibrate my Tacx smart trainer as I always get the message that the bike a Giant Defy (2014)is too loose in the stand .

    1. Hi Nigel. Sorry to hear you’re having a problem, but our site is strictly for Tacx Neo. It does not sound like you have a Neo, so we will not be able to provide any clues as to the problem.

  2. Do you think it’ll be a problem if I use a 1/2″ drill bit, instead of 12mm? It’s slightly larger.

  3. Hi there, I have a problem with my Tacx Neo 2. The problem is that the chain always jump on the smallest cog so I cannot use the trainer.
    My bike is Bianchi Oltre 3 with 11 cog rings at the back and also on the trainer.

    Best regards

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