If I choose a Sender CFR 29er can I ride it with a mullet setup?
No, that does not work due to the different geometries. Fitting a 27.5″ wheel in a 29″ rear triangle would result in the bottom bracket being too low. The shock mount indicating is only labelled 27.5/29 because both bikes use the same MX link.
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Canyon consistently strives to ensure the quality and accuracy of the information contained in this Technical Support Centre. Any repairs or adjustments which you carry out on your bike are entirely at your own risk. If you are in any doubt what to do, you should send your bike to Canyon or take it to another qualified specialist. Canyon gives no guarantee or accepts no liability for any of the information contained in this Technical Support Centre.