Kickr Core - Inner Hub Spacer not fitting Zwift Cog


A week ago I purchased Kickr Core (with 12 Speed Cassette) and Zwift Cog.
The Zwift Cog installation video, guided to keep the inner freehub spacer.
When installing the Zwift Cog, the spacer’s diameter is a little off, and is now fully stuck in my freehub spacer.
Fortunately, I had a spare freehub but I don’t have the inner spacer.

Three Questions:

  1. Am I correct that the inner spacer is required?
  2. Where can I get a new inner freehub spacer for the Kickr Core?
  3. Am I correct in that the spacer should easily fit into the Zwift Cog ?

Many thanks

Hi @Benjamin_Moore_RBN , welcome to the Zwift Forums! The Zwift Cog is only intended to be compatible with the Zwift Hub. I do not recommend attempting to install the Cog onto a Kickr Core as there’s a risk of damaging any of the parts involved.

Hi Rowdy,

Thanks. I did not realize that.

Is it possible to get the inner freehub spacer for the CORE. I can then put back on the 12 speed cog set?


It’s an 11 speed freehub body, so you don’t need a spacer for a 12 speed cassette. The 1.8mm spacer is used for 8-10 speed cassettes, and a few 11 speed cassettes designed for a 10 speed freehub body.

In any case you can find a 1.8mm cassette spacer at any bike shop, Amazon, etc.

Wahoo’s advice about cassette installation:

Hi Paul,

Thanks for the reply. Keep in mind I am referring to the spacer, inside the freehub itself, not the gear spacer. See below… (note these are images from the web and not my images specifically)