RockShox

SID SL Ultimate Race Day 29in Boost Fork

What Our Gearhead® Experts Are Saying:

"I installed this fork for marathon XC racing, and it’s been flawless. The 2-position remote setup is simple and race-effective—I can lock it out and sprint, then open it for descents with one motion. It’s the perfect match of lightness and control for serious racers."

The RockShox SID SL Ultimate 2 Position fork is the definition of speed-focused precision. Purpose-built for cross-country racing and long-distance events, it blends ultralight construction with responsive, rider-controlled damping. With 100mm or 110mm travel options and a 44mm offset optimized for fast 29-inch bikes, it delivers exactly the support racers need—no more, no less. The updated Charger Race Day 2 damper features two ride modes—Open and Lock—activated by a remote system (sold separately) for instant on-the-fly suspension changes.

This fork is built around RockShox's most refined small-bump technology: the DebonAir+ spring. Tuned for a plush early stroke and supportive mid-travel, it boosts control and grip across technical XC terrain. The forged, hollow aluminum crown and magnesium lowers ensure that every gram is put to work, while increased bushing overlap boosts stiffness and improves long-term durability. Fast Black-coated 32mm aluminum stanchions ensure low-friction performance even under heavy race loads.

With a BOOST 15x110mm axle, compatibility with flat-mount disc brakes, and clearance for 755mm diameter tires, the SID SL Ultimate 2 Position is ready to slot into any modern XC race rig. It’s the fork we trust when margins are razor-thin and performance can’t be compromised.