Actually, Cannondale used the 1 1/4" headset when they came out with the Headshok. So now young Cheeto...you have 1", 1 1/8", 1 1/4", and the good ol' 1 1/2". Oh yeah...lemme throw another coal on the fire for you. Tapered steerer tubes. 1 1/2" lower headset cup with 1 1/8" top cup.