The SRAM XX1 Groupset has been built with a dedicated 1X drivetrain philosophy which allows it to be simpler, lighter & more durable. The XX1 was built to be at home & excel at everything from elite XC racing & enduro racing to high performance trail riding for people that are serious about their bikes & serious about performance. This groupset does not include a chainring, allowing you to buy your ideal chainring size to match your desired gearing set up.