RockShox SID Ultimate Race Day 2 Suspension Fork - 29" 120 mm 15 x 110 mm 44 mm Offsett Electric Red 3P Crown D1. Climb mountains. Charge descents. The RockShox SID Ultimate isnt like other XC forks. It is lighter than ever with a formidable 35mm chassis that holds the line when youre on the edge. The Race Day 2 damper provides efficient Pedal positions all at your fingertips. SID Ultimate adapts to everything from full-gas cross-country to sporty backcountry loops thanks to a new higher-volume DebonAir spring thats supple at the top of its travel with tons of tunability.