Question: what is the difference between xd and xdr?
Answer: The XDR interface is 1.85mm longer than XD and is designed for road hub applications. XDR maintains the same hub spacing and flange locations used for 11-speed road compatible HyperGlide freehub bodies. XDR driver bodies are compatible with all XD cassettes when the cassette is installed with a 1.85mm spacer behind it.