About the Sirrus X 2. 0 Sirrus X is your ticket to riding more, and to places you never imagined possible. It's a comfortable, capable, let's do stuff kind of bike that will inspire you to ride more than you ever have before. With bigger, confidence inspiring tires, a slightly more upright riding position, a super intuitive one-by drivetrain, and plenty of mounts for racks and fenders -it's more than just a solid partner on pavement. Sirrus X is a dialed option when it's time to hit some gravel.