Zipp Service Course SL Stem - 31.8mm Clamp, +/-17°, 1-1/8", Matte Black
The Zipp Service Course SL Stem is a lightweight performance stem built from forged 7075 aluminum for riders who want precise front-end stiffness, reliable fit adjustment, and long-term durability. Designed for road, gravel, and performance builds, it uses a proven 31.8mm clamp standard with a reversible +/-17° angle for aggressive race positioning or taller front-end fit corrections.
Key Functional Details
- Available in 70mm, 80mm, 90mm, 100mm, and 110mm lengths
- 31.8mm handlebar clamp diameter
- Fits 1-1/8" steerer tubes (28.6mm)
- +/-17° reversible angle for fit adjustment flexibility
- Forged AL-7075 aluminum construction
- Machined and relieved faceplate for reduced weight
- Titanium hardware with TORX heads for precise torque readings
- Matte Black finish
- Built for strong sprint response and no-flex accelerations
Technical Specifications
| Brand | Zipp |
| Model | Service Course SL Stem |
| Available Lengths | 70mm / 80mm / 90mm / 100mm / 110mm |
| Bar Clamp Diameter | 31.8mm |
| Steerer Clamp Diameter | 28.6mm (1-1/8") |
| Stem Angle | +17° / -17° |
| Material | Forged AL-7075 Aluminum |
| Hardware | Titanium TORX Bolts |
| Stack Height | 41mm |
| Color | Matte Black |
| Country of Origin | Imported |
Compatibility & Technical Notes
Good Fit: Riders using standard 31.8mm handlebars and 1-1/8" steerer tubes on road, gravel, cyclocross, and aggressive endurance bikes. Strong fit for riders dialing in reach and bar height after a professional bike fit.
Not A Fit: Not compatible with 35mm handlebars. Not for oversized steerer standards beyond 1-1/8". Not ideal for riders who need an upright comfort-first position unless geometry supports the stem angle and stack.
The +/-17° angle gives significantly more fit adjustment than common +/-6° stems. This makes it useful for both lowering the front end on race bikes and correcting fit issues without changing the entire cockpit. Always verify both bar clamp size and steerer diameter before ordering.
Service / Ownership Context
This is one of the best alloy stem upgrades for riders replacing heavy OEM stems or refining bike fit after a professional sizing session. The titanium TORX hardware improves torque consistency, especially when paired with carbon handlebars. This is a performance fit component—not just a cosmetic upgrade—and proper stem length selection directly affects handling and rider comfort.
Fit & Use Signals
- Best for road and gravel riders optimizing fit and handling
- Excellent for aggressive race positioning and front-end stiffness
- Good for upgrading from heavy stock stems
- Strong match for carbon bar setups requiring precise torque control
- Not compatible with 35mm cockpit systems
