The of XD vs. XDR freehub drivers were covered in a previous article about the ingenious MFU axle design. However, the matter at hand has so much weight that it deserves an own – but brief – article of its own. On top of that Onyx Racing Products came up with an excellent video covering the subject which is found below.
XD and XDR Standards
Since the introduction of the MFU axle design, Onyx Racing Products hubs only been supplied with the Sram XDR driver. This has been a source of confusion from time to time since the majority of mountain bike cassettes employ the XD standard.
Conveniently, the XDR can be converted to XD with the use of a 1.85mm spacer that’s supplied with all XDR-equipped hubs. Please see the video below to see the instructions and how the interface works.
| Interface standard | 1.85mm spacer installed | Notes |
| XDR | No | Mostly seen in road bikes |
| XD | Yes | Commonly used in MTB components |
HG-11 and 10
The same thing applies to Shimano HG freehubs since those are also supplied with an identical spacer. HG interface works
| Interface standard | 1.85mm spacer installed | Notes |
| HG-11 | No | The most common standard used in MTB, gravel and road bikes. |
| HG-10 | Yes | An old standard that’s rarely used |
Conveniently, Onyx Racing Products has made a very informative video about this subject as well.
Driver Material
Armed with this information, one can easily choose the correct freehub driver. With Classic and single-speed specific HG-SS hubs the only thing left is to choose the driver material. Luckily, we got you covered and have covered this subject at length in a previous article.