The Sirrus X offers an unprecedented combination of comfort, efficiency, and agile handling, excelling on asphalt, gravel, and any terrain in between. COMFORTABLE, SMOOTH, AND EFFICIENT: The Sirrus X offers the smoothest ride in its class. With wider, confidence-inspiring tires, a slightly more upright seating position, and a super intuitive one-by drivetrain. RIDER-FIRST ENGINEERED™: At Specialized Bikes, every single frame size and geometry is individually designed rather than just 'shrunk'. For each size, tube lengths and diameters are examined for optimal balance of stability, weight, and responsiveness. The goal? No matter what frame size you ride, we ensure you have the best riding experience in the world. COMFORTABLE: Industry-leading weight, exceptional pedaling efficiency, and flexible handling combine for almost telepathic riding characteristics.