Question 1

What is the difference between XD and XDR?

Accepted Answer

Both are SRAM driver bodies with no separate lockring, allowing a 10-tooth smallest cog. XDR is 1.85 mm longer than XD. XD is the mountain-bike standard (SRAM Eagle), XDR is the road and gravel standard (SRAM AXS).

Question 2

Can I fit an XD cassette on an XDR body?

Accepted Answer

Yes — an XD cassette mounts on an XDR driver body if you add a 1.85 mm spacer behind it. The reverse does not work: an XDR cassette is too long for an XD body.

Question 3

Which one does my bike use?

Accepted Answer

If your bike runs SRAM Eagle (1×11 or 1×12 MTB) it uses XD. If it runs SRAM AXS road or gravel (Rival/Force/Red), it uses XDR. Shimano drivetrains use HG or Micro Spline instead — see the identify-your-freehub guide.

Question 4

How many speeds do XD and XDR support?

Accepted Answer

XD takes 11- and 12-speed SRAM cassettes; XDR takes 11-, 12- and 13-speed cassettes. Both go down to a 10-tooth smallest cog, which a standard HG body cannot do.

Question 5

Which smart trainers work with XD or XDR?

Accepted Answer

In our database 17 trainers offer an XD body and 21 offer an XDR body — usually sold as a separate driver you swap on. The list above shows each one.

Property	SRAM XD	SRAM XDR
Typically used on	MTB (SRAM Eagle 1×)	Road & gravel (SRAM AXS)
Cassette speeds	11–12-speed	11–13-speed
Smallest cog	10t	10t
Driver length	Reference (shorter)	1.85 mm longer than XD
Cross-compatibility	XD cassette → fits XDR body with a 1.85 mm spacer	XDR cassette → will not fit an XD body

XD vs XDR freehub body

XD vs XDR side by side

Which trainers support XD and XDR

Frequently asked questions