Wolf Tooth Components have built their reputation on quality Drop-Stop chainrings that are made in the USA. Part of that has to be their knack for offering solutions to drivetrain and BCD problems before we knew they existed. When it comes to the new M9000 crankset, not only is there a different BCD which is also found on the XT M782 and SLX M672 cranksets, but there is also a new bolt system for XTR.
The new Elliptical chainring design is said to provide greater efficiency and smoothness when it comes to power output. In Wolftooth's on words 'The simplest way to explain how they feel is that where your pedal stroke is weakest it feels like you have 2 less teeth on the chainring and where you have the most power it feels like have 2 more teeth'.