disco flottante sram centerline x center lockThe Sram Centerline Rounded floating rotor maintains a uniform friction area during rotation that limits vibrations and noise. It ensures consistent, high performance, and quiet braking. The floating design dissipates heat more easily and better absorbs mechanical stresses. Features Material: aluminum carrier, steel braking surface. Actual Center Lock weight: 104 g (140 mm), 119 g (160 mm), 140 g (180 mm). Versions Center Lock: locking ring not