The RockShox SID SL Ultimate 2P is an ultra-lightweight, high-performance cross-country suspension fork designed for racers and aggressive XC riders. Engineered for efficiency and stiffness, it offers riders a two-position (2P) remote lockout system, perfect for quickly switching between full travel and a fully locked-out mode. To maintain peak performance, periodic servicing—including a complete rebuild—is essential. This guide outlines the comprehensive steps required to rebuild the SID SL Ultimate 2P, covering installation tips, troubleshooting, customization, and component compatibility.
Tools Required
- 24mm and 32mm sockets
- Torque wrench [paid link]
- Suspension fork pump
- Flat-blade screwdriver
- Pick tool
- Plastic syringe or oil damper bleed kit [paid link]
- RockShox 0W-30 suspension oil
- RockShox 5wt damper fluid
- RockShox butter grease
- Clean rags
- Isopropyl alcohol
- Seal kit and replacement o-rings (specific to SID SL Ultimate 2P)
- Gloves and eye protection
Understanding the SID SL Ultimate 2P Fork Architecture
The SID SL Ultimate 2P uses a Charger Race Day damper and DebonAir air spring. Its crown-steerer-upper assembly is one piece for increased stiffness and reduced weight. The fork is designed with 32mm stanchions and features a two-position lockout integrated with a remote.
Disassembly Process
Begin by releasing air pressure from the fork. Unscrew the air cap on the left leg and depress the Schrader valve. With the fork inverted, remove the lower leg bolts using a 24mm socket for the damper side and a 10mm hex for the air side. A few gentle taps on each bolt will dislodge the inner assemblies from the lowers. Carefully slide the lower legs off and drain the residual oil.
Remove the air spring assembly from the left leg by unthreading the top cap. On the right leg, unthread the damper top cap and slowly pull the Charger Race Day damper cartridge out of the stanchion. Note the orientation and placement of spacers, seals, and compression valves for reassembly.
Inspection and Cleaning
With all components removed, clean them thoroughly using isopropyl alcohol. Pay close attention to the inner surface of the stanchions and the fork lowers. Inspect the bushings, air spring seals, and damper shaft for scoring, excessive wear, or contamination. Replace any seals that appear brittle, cracked, or deformed.
Replacing Seals and Lubricating Components
Install new wiper seals and foam rings into the fork lowers. Soak the foam rings in 0W-30 oil before installation. Rebuild the air spring by replacing o-rings and applying RockShox butter grease to each seal. Reinsert the air spring into the left leg and torque the top cap according to RockShox specifications.
For the damper, refill the cartridge with RockShox 5wt oil using a syringe or damper bleed kit [paid link]. Ensure no air bubbles remain. Reinstall the Charger Race Day damper and torque the top cap properly.
Reassembling the Fork
Slide the fork lowers back onto the stanchions carefully. Inject 10ml of 0W-30 oil into each leg through the bottom before reinstalling the bolts. Tap the bolts gently to seat the assemblies, then torque them to spec. Re-pressurize the air spring to your desired setting based on rider weight and sag recommendations.
Test the fork’s movement and function through its full range of travel. Confirm that the lockout switches between full open and locked out with minimal lag or sponginess.
Troubleshooting Common Issues After Rebuild
If the fork feels sticky or harsh, inspect the wiper seals and ensure oil volume was correct. A noisy rebound circuit often indicates trapped air or incorrect damper bleed. If lockout is unresponsive, verify that the remote is properly indexed and that the damper shaft is not over-torqued. Always cross-check against RockShox’s recommended specifications during rebuilds.
Optimizing the SID SL Ultimate 2P for Performance
Customization options include modifying the air spring volume with RockShox Bottomless Tokens to adjust ramp-up characteristics. Riders preferring a firmer platform may opt for a slightly higher pressure setting. Additionally, remote cable tension can be fine-tuned for more immediate lockout engagement.
For enhanced responsiveness, apply a light coat of RockShox butter grease to the upper bushing area and use a fresh set of foam rings at every service interval. Aligning the bushings during reassembly ensures smoother stanchion travel and extends fork life.
Compatibility with Other Components
The SID SL Ultimate 2P is designed for 100mm travel setups and uses a straight 32mm stanchion configuration, making it compatible with RockShox’s own crown race and control systems. Its Charger Race Day damper is exclusive to this model and should not be swapped with non-SID dampers. It pairs best with 1.5″ tapered headsets and flat-mount brakes for optimal weight and integration.
It is also compatible with TwistLoc and OneLoc remotes but requires careful tensioning and setup for seamless operation. Always ensure the fork axle type and offset match your frame geometry for best results.
Comparison with Similar Models
Compared to the RockShox SID Ultimate (non-SL), the SL variant is lighter due to its narrower stanchions and lack of compression adjust features beyond lockout. While this limits tunability, it enhances weight savings and responsiveness for XC courses.
Fox 32 Step-Cast forks in the same weight category offer a similar lockout system but use a FIT4 or GRIP damper. The SID SL Ultimate 2P holds an edge in simplicity and ease of maintenance due to the external damper bleed port and minimalistic architecture.
Conclusion
Rebuilding the SID SL Ultimate 2P fork is a straightforward but detail-sensitive task that ensures your fork continues to perform at its highest level. By following precise steps for disassembly, inspection, seal replacement, and reassembly, you can maintain factory-level performance or even enhance it through customization. With proper care, this ultra-lightweight suspension fork remains a formidable tool for competitive cross-country racing.