The RockShox SID SL Ultimate 2P is a premium cross-country suspension fork engineered for racers who demand top-tier performance in the lightest possible package. It combines advanced damping technology, structural refinement, and weight-saving features to meet the unique challenges of competitive XC riding. This guide explores its key features, installation process, tuning and maintenance, and how it compares with similar models in its class.
Tools Required:
- Torque wrench [paid link]
- Allen key set (primarily 2mm to 6mm)
- Suspension pump
- Star nut setter (if applicable)
- Crown race setting tool
- Shock pump
- Grease and carbon assembly paste
Construction and Design Highlights
The SID SL Ultimate 2P features a minimalist yet robust design. The chassis is crafted with magnesium lowers and a hollowed-out crown to maximize stiffness-to-weight ratio. The 32mm stanchions are anodized for smooth action and durability. It is optimized for 100mm of travel and is compatible with 29-inch wheels, a staple in modern XC racing setups.
Its One-Piece Magnesium lower legs reduce flex under high load, while the machined and anodized crown reduces overall weight without sacrificing integrity. These design elements contribute to its status as one of the lightest race-day forks available.
Damping System: Charger Race Day 2 Damper
At the core of the SID SL Ultimate 2P lies the Charger Race Day 2 damper. This two-position system (Open and Lockout) offers simplicity for race environments where instant terrain adaptation is vital.
In Open mode, the damper provides active suspension with refined low-speed compression control, making it responsive over roots and small bumps. The Lockout mode is engineered to eliminate fork movement entirely, ideal for sprints and climbs. The transition between modes is immediate, promoting efficiency and traction management without distraction.
Installation Procedure
Installing the SID SL Ultimate 2P requires precision to maintain its performance and warranty conditions. Start by measuring and cutting the steerer tube to fit your frame’s head tube. A star nut or compression plug must be installed depending on whether a carbon or alloy steerer is used.
Mount the crown race using the appropriate tool and ensure it sits flush against the base. Insert the fork into the head tube, align with the stem and spacers, and tighten the top cap. Secure the stem bolts to the recommended torque. Axle installation must be performed using the Maxle Stealth thru-axle system, which minimizes weight and simplifies wheel changes.
Air Spring Adjustment and Setup
The DebonAir air spring in the SID SL Ultimate 2P is tailored for riders seeking a plush, supportive beginning stroke. It uses a large negative air chamber to keep initial movement smooth while retaining mid-stroke support.
To tune the air spring:
- Set the desired sag using a shock pump and the manufacturer’s pressure chart.
- Check that the O-ring rests 15-20% down the stanchion when the rider is seated in full gear.
- Fine-tune rebound damping with the red adjuster at the bottom of the right fork leg.
This setup allows tailored rider weight and style customization, a critical factor in cross-country performance.
Maintenance Guidelines
Regular maintenance ensures optimal performance and prolongs fork lifespan. After every 50 hours of use, perform a lower leg service to clean and replace the foam rings and bath oil. The Charger Race Day 2 damper should be serviced every 100 hours or annually.
Clean the stanchions and seals after every ride. Use suspension-specific lubricants and avoid power washing directly on the seals or damper.
Troubleshooting Common Issues
Some riders experience harsh top-out or inconsistent rebound. These are often caused by incorrect air pressure or damper settings. If the fork feels sticky or noisy, inspect for debris under the seals or dried-out foam rings.
Air loss can stem from damaged Schrader valves or improper torque on the air cap. For lockout issues, ensure the cable tension (on remote models) is properly adjusted and that the damper cartridge is functioning.
Tuning and Optimization Tips
Advanced riders may install volume spacers to modify spring curve progression. Fewer spacers yield a more linear response; adding spacers increases end-stroke ramp-up, useful for aggressive terrain.
Adjusting rebound to match terrain and rider input speed enhances ride quality. On smooth courses, a faster rebound gives better control, while a slower setting improves stability on technical descents.
Compatibility with Drivetrain and Frame Standards
The SID SL Ultimate 2P uses a Boost hub spacing (110mm x 15mm), ensuring compatibility with modern XC wheelsets. It fits flat-mount disc brakes with a direct-mount 160mm post, adaptable up to 180mm.
The fork’s axle-to-crown measurement of 506mm (for 100mm travel) aligns well with XC geometry. It pairs best with carbon or alloy frames designed for steep seat angles and slack head tube angles common in race setups.
Comparison with Similar Models
When compared to the Fox 32 Step-Cast Factory, the SID SL Ultimate 2P is slightly lighter and offers a more responsive lockout. The Charger Race Day 2 damper is more minimalist, while Fox offers greater adjustability with open, medium, and firm compression settings.
Versus the DT Swiss F 232 One, the SID SL Ultimate 2P has superior serviceability and availability of spare parts. However, DT Swiss wins on pure weight savings, making it attractive for ultra-weight-conscious riders.
Remote vs. Crown Actuation
The SID SL Ultimate 2P is available in both remote and crown-actuated lockout options. Remote lockouts offer ergonomic advantage, letting riders toggle modes without changing hand position. This is particularly beneficial in races with frequent terrain shifts.
Crown-actuated models are more suitable for riders prioritizing simplicity or minimizing cockpit clutter. Both systems utilize the same internal damper, ensuring performance parity.
Customization Options
Riders can personalize the SID SL Ultimate 2P with aftermarket decals or color-matched graphics to match frame aesthetics. Titanium bolts or carbon steerer tubes may be fitted to shave off additional grams for weight weenies.
Swapping the remote lever for different models such as the TwistLoc or OneLoc can also enhance ergonomics and bar compatibility.
Remote Lockout Cable Setup
Ensure the remote cable is routed cleanly with no kinks. The barrel adjuster must be backed out before tightening the anchor bolt at the fork. After initial setup, fine-tune tension at the remote to allow precise engagement without lag or stiffness.
Proper cable tension ensures consistent mode shifts, especially under load or during fast transitions in a race scenario.
Best Use Cases for This Fork
The SID SL Ultimate 2P is optimized for short-travel cross-country and marathon racing. Its light chassis and effective damping make it ideal for fast, rolling terrain with moderate technical features.
It is not suitable for aggressive trail riding or enduro use, as the narrow stanchions and limited travel limit its descending capabilities.
Weight and Offset Options
Weighing in at approximately 1,326 grams (without remote or axle), this fork leads the segment in minimalism. Available offsets (44mm typical) allow riders to dial in their bike’s trail and steering response for sharp, responsive handling.
Pros and Cons Summary
Pros:
- Ultra-lightweight chassis
- Refined damper with precise lockout
- Easy setup with air spring and rebound adjust
- Ideal for race-focused applications
Cons:
- Limited adjustability compared to trail forks
- Requires frequent maintenance for peak performance
- Not suited for aggressive descending
FAQs
What is the recommended air pressure for the SID SL Ultimate 2P?
Refer to RockShox’s rider weight chart, but typically it ranges from 70 to 120 PSI depending on rider weight and sag preference.
Can I use this fork on a trail bike?
No. It’s designed strictly for cross-country use and lacks the structural integrity for aggressive trail conditions.
How often should I service the damper?
Every 100 hours of riding or annually, whichever comes first.
Does it come with a remote lockout?
Some versions include a remote lockout; verify your specific model’s SKU.
What’s the difference between the SID SL and regular SID?
The SID SL is lighter and limited to 100mm travel, whereas the SID is available in longer travel and stiffer stanchion options.
Is this fork compatible with a 180mm rotor?
Yes, but an adapter will be required to step up from the default 160mm post mount.