The RockShox SID SL Ultimate 2P is a race-focused, cross-country suspension fork that merges low weight with highly responsive damping performance. Designed for elite riders, this fork emphasizes speed, precision, and fine-tuned control over technical terrain. This guide outlines detailed instructions on installing, adjusting, maintaining, and optimizing the SID SL Ultimate 2P for maximum performance.
Tools Required
- 6mm and 2mm Allen wrenches [paid link]
- Torque wrench [paid link] with Nm calibration
- Crown race setting tool
- Shock pump (accurate to 1 psi)
- Suspension grease and isopropyl alcohol
- Star nut setter and hacksaw (if steerer needs trimming)
- RockShox Maxima Plush fluid and lower leg service kit
- Clean rag and nitrile gloves
Installation Guide
Correct installation of the SID SL Ultimate 2P is essential to maintain structural integrity and performance. Begin by confirming compatibility with your frame’s axle-to-crown and offset specifications.
The tapered steerer must be cut to the correct length based on the stack height and desired bar position. Use a guide tool and measure twice to avoid over-cutting. Fit the star nut using a setting tool to the recommended depth. Press the crown race using the proper race setting tool to avoid damage to the fork’s steerer tube.
Once the fork is in the headset, torque the stem bolts and top cap to RockShox’s specified values, typically between 4-6 Nm. Mount the front wheel and align the brake caliper ensuring even rotor spacing. Use a torque wrench [paid link] to secure the thru-axle to 8 Nm.
Initial Setup and Air Pressure Adjustment
To optimize the SID SL Ultimate 2P’s performance, begin by dialing in the air spring pressure using the RockShox chart or SRAM TrailHead tuning guide. Pressure is adjusted through the Schrader valve at the top of the fork leg. Match the rider’s weight with the recommended PSI to set sag between 15-25%.
Set the rebound adjuster knob (located at the bottom of the fork leg) based on rider preference and terrain, typically starting at the middle setting and making small adjustments per ride feedback.
The two-position damper—Open and Lock—should be tested during short rides to evaluate platform firmness and responsiveness. Ensure the fork fully extends and compresses without topping out or harsh bottoming.
Maintenance Procedures
Routine maintenance ensures the SID SL Ultimate 2P performs consistently over time. Every 50 hours of riding, perform a lower leg service. Remove the fork lowers carefully and drain the old Maxima Plush fluid. Clean stanchions, wiper seals, and foam rings using isopropyl alcohol. Re-grease and reinstall with new fluid (10 ml per leg).
Every 100-200 hours, conduct a full damper and air spring rebuild. This requires more advanced knowledge and is best done with RockShox service manuals or by a qualified technician. Inspect for wear on bushings and replace any damaged seals to prevent long-term performance loss.
Keep the fork clean after every ride, especially in muddy conditions. Wipe down stanchions and re-lube seals to prevent dirt ingress.
Troubleshooting Common Set-Up Issues
If the fork feels too harsh, the air pressure may be too high or rebound too fast. Adjust by lowering PSI incrementally and opening the rebound dial. Spongy travel often indicates low pressure or air spring leaks, which may require seal inspection.
Knocking or excessive play could suggest loose headset components or a worn bushing. Check all torque settings and perform a bushing overlap test by compressing and twisting the fork under load.
If the Lock mode fails to engage, check the remote cable tension or internal damper mechanism. The 2P damper should audibly click when switching modes.
Customization and Performance Optimization
The SID SL Ultimate 2P allows fine-tuning for race-day setups. Riders can experiment with volume tokens in the air spring to increase ramp-up and bottom-out resistance. Installing an extra token enhances progressive support on rough terrain.
Remote lockouts can be upgraded to RockShox TwistLoc or OneLoc systems for more ergonomic control. Ensure cable routing is smooth and doesn’t introduce friction, which can degrade lockout performance.
Upgrade the fork oil to a lighter viscosity in colder climates or use performance-tuned seals to reduce breakaway friction. Such changes improve small bump compliance and reactivity under low-speed compression.
Compatibility with Other Drivetrain Components
The SID SL Ultimate 2P is designed for cross-country setups with 100mm or 110mm travel configurations. It uses a 44mm offset and Boost 15x110mm axle spacing. Ensure the front hub is Boost-compatible and that the rotor size aligns with the fork’s maximum rating (typically 180mm).
For drivetrains, it complements lightweight XC components from SRAM and Shimano, especially with remote lockouts integrated into combination levers. Frame compatibility must account for crown clearance and cable routing if using internal lockout remotes.
Brake compatibility includes post-mount systems; adapters may be needed for rotors above 160mm.
Comparison with Similar Models
Compared to the standard RockShox SID, the SL Ultimate 2P sheds additional weight with a machined crown and carbon steerer. It’s designed for weight-conscious racers who prioritize agility.
Versus the Fox 32 Step-Cast, the SID SL Ultimate 2P offers similar weight but with a different damping feel. RockShox leans toward a more active, supple stroke while Fox emphasizes mid-stroke support.
The 2P damper is simpler than the 3P found in some other SID variants, offering Open and Lock modes only. This reduces complexity and failure points, ideal for competitive riders who demand reliability and simplicity.
Conclusion
The RockShox SID SL Ultimate 2P is engineered for competitive cross-country riders who require lightweight precision and consistent damping performance. With correct setup, regular maintenance, and thoughtful customization, it delivers a transformative experience on demanding trails.
Frequently Asked Questions
1. How often should I service the SID SL Ultimate 2P fork?
Service the lower legs every 50 hours and perform a full rebuild every 100-200 hours depending on riding conditions.
2. Can I install this fork on a trail or enduro bike?
No. This fork is optimized for cross-country bikes and is not suitable for aggressive trail or enduro riding due to its limited travel and chassis design.
3. What is the maximum rotor size supported?
The maximum rotor size for the SID SL Ultimate 2P is typically 180mm. Check RockShox specifications for confirmation before installation.
4. How do I know the correct air pressure for my weight?
Use the RockShox air pressure chart or the SRAM TrailHead app to determine the correct PSI based on your body weight and riding style.
5. Why isn’t the lockout working properly?
Check for cable tension if using a remote. If the fork is not locking out manually, internal damper service may be required.
6. Can I convert this fork to have more travel?
No. The SID SL Ultimate 2P is factory-set for 100mm or 110mm travel and cannot be extended without changing internals and voiding warranty.