At its heart, XX1 is a drivetrain system geared around a single chainring, mated to a gargantuan, 11-speed (10 x 42) cassette. If you already run a “one by” system on your bike, you probably see where this is going: it’s a simpler system with a much wider gear range than anything you could cobble together with existing 10-speed parts. For more info on the SRAM XX1, click here.

Photo courtesy Bike