Early production versions of HB50 Piedmont hubs can have tolerance stack resulting in clearance issues if used with new 13 speed SRAM drivetrains. 

This issue has been resolved with updated axle endcaps. To identify the updated endcap, there is a groove that has been added to the endcap on the updated versions. 

If you have one of the original versions and need the updated axle, please reach out to us and we will supply it. 

This does not apply to older Piedmont hubs with 15mm axles.

Here is the location of the groove on the Drive side Axle endcap: