The Sirrus X offers an unparalleled combination of comfort, efficiency, and nimble handling, excelling on asphalt, gravel, and any terrain in between. COMFORTABLE; SMOOTH AND EFFICIENT: The Sirrus X provides 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 tested for their optimal balance of stability; weight, and responsiveness. The goal? No matter what frame size you ride; we ensure you have the best ride feel in the world. COMFORTABLE: Industry-leading weight, exceptional pedaling efficiency, and flexible handling come together for nearly telepathic riding characteristics.