Thule's Prologue Pack is an all-in-one solution for attaching 2 bikes to your factory rack. It includes 2 Prologue trays with a secure load bar. They're compatible with bicycles featuring standard forks, including carbon forks and those with disc brakes. The mount's trays accommodate tires up to 2.6-inches wide. The Prologue fits round, aero and square crossbars, too. Plus, the fork mount features a dual-lock head that locks your rig to the mount and locks the mount to the rack.