Inner soft gripper elastic on bottom hem
without constricting any upper body movements
Compatible with electronic drivetrains only
it's important to capitalize on years of R&D and pro rider feedback to create the fastest time trial bike—for all courses
11% more efficient and 5% lighter than any other endurance tire on the road*
Sirrus X 4.0 Gravel Inner soft gripper elastic onOffering an unprecedented combination of comfort, efficiency, and nimble handling, the Sirrus X excels on pavement, dirt, and any terrain in between. SMOOTH; COMFORTABLE, AND EFFICIENT: Sirrus X provides the smoothest ride in its class. With bigger, confidence inspiring tires, a slightly more upright riding position, and a super intuitive one by drivetrain. RIDER FIRST ENGINEERED: Like all Specialized performance bikes, the geometry of each frame is