Issues fitting a SRAM 12-speed AXS cassette to Tacx Flux S


I’ve just upgraded to a new Orro Venturi STC Force AXS. It’s a lovely bike and I invested in a spare Rival AXS cassette and Tacx XDR body so I can put it on my Flux S trainer.

But I’m struggling to get the cassette to be seated properly. It’s about 1-2mm proud of where it should be sitting and I can’t seem to tighten it any further for love nor money. Even tighetening it to where it is takes way more force than it does on my Fulcrum wheels that came with the bike.

I can’t use my trainer because the gears are out of alignment, and the 10t cog is butting right up against the frame.

Any ideas?

I don’t have the XDR hub body for my Flux S as I’ve got a 9 speed bike on the trainer, but is there a spacer on there that shouldn’t be there when using a 12 speed cassette?

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I would think that ^^ is what’s going on. Despite them giving you a spacer with the hub, you’re not actually supposed to use the spacer with an XDR cassette. That’s so you can stick an XD cassette on, if you so choose.

Hopefully it was just this simple.


Thanks - but I haven’t added a spacer. Would there already be one on the hub/axle?

SpiderJ - did this get resolved? I am about to install the same thing…

What I’ve done is get a ZTTO 12 speed cassette and put that on instead.
Works fine for erg mode, and shifting is 90% of the stock SRAM one. Only runs into issues towards the small end of the cassette (and that might just be because I can’t be bothered adjusting my shifting for the trainer)
Cost was less than an XDR converter would be for my Elite Directo

In the end, it turned out that the cassette was faulty - the thread on the inside of it was damaged on arrival.

the XDR thread system is meant to be easier to get on the hub than the Shimano Spline system - but it seems too easy for it to be misthreaded

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