The SRAM Force eTap AXS D2 HRD [paid link] brake system is a top-tier hydraulic disc setup tailored for gravel and endurance riders seeking smooth, reliable modulation with wireless shifting integration. This guide walks you through the complete installation, setup, and optimization of this system specifically for gravel bike applications.
Tools Required
- T25 and T10 Torx wrenches
- 5mm and 4mm hex keys
- Hydraulic brake hose cutter and barb press
- Bleed kit (SRAM Bleeding Edge compatible)
- DOT 4 or DOT 5.1 brake fluid
- Torque wrench
- Cassette lockring tool (for rotor installation)
- Clean gloves and isopropyl alcohol
- Bleed block and rotor pad spacer
- Internal cable routing tool (if needed)
Understanding the SRAM Force eTap AXS D2 HRD System
The Force eTap AXS D2 HRD system combines SRAM’s updated wireless eTap shifting with hydraulic disc braking, integrating a cleaner hood shape and revised ergonomics over the previous generation. It’s fully compatible with other AXS components and designed to excel on mixed terrain, making it ideal for gravel riding.
Pre-Installation Checks
Before starting the installation, inspect the frame and fork for flat-mount disc brake compatibility. Confirm internal routing ports for hydraulic hose passages and ensure no debris blocks any ports. Check that your frame spacing and rotor size match SRAM recommendations—typically 160mm rotors front and rear for gravel.
Installing Brake Calipers and Levers
Brake Calipers
Begin by mounting the calipers using the appropriate flat-mount adapters. For most gravel bikes, this will require the use of a 20mm adapter in front and no adapter in the rear if using 160mm rotors. Lightly thread the bolts with a T25 Torx wrench, ensuring that the caliper sits centered over the rotor.
Brake Levers
Slide the lever assemblies onto the bar and position them according to rider preference, typically aligning the hoods with a flat plane from the drops. Tighten clamp bolts evenly using a 4mm hex key to avoid misalignment. Torque to 6 Nm once positioning is finalized.
Cutting and Connecting Hydraulic Hoses
Measure hose lengths with the handlebar turned fully left and right, leaving a small loop for flexibility. Cut using a proper hose cutter to ensure a clean edge. Insert barbs and compression olives using SRAM’s dedicated barb press tool.
Insert the hose into the lever body port and tighten the compression nut with a torque wrench to 5.5 Nm. Route the hose internally using a cable guide tool where applicable and secure with frame grommets.
Rotor and Pad Installation
Install rotors using a cassette lockring tool, torquing the centerlock to 40 Nm. Clean the rotor with isopropyl alcohol before inserting brake pads into the caliper. Use SRAM’s included pad spacers to prevent pad contamination and maintain alignment during bleed.
Bleeding the Hydraulic System
The Force eTap AXS D2 HRD uses SRAM’s Bleeding Edge system for simple and clean fluid changes. Install the bleed block into the caliper and connect the syringe via the Bleeding Edge fitting. Follow SRAM’s standard bleed procedure using DOT 4 or 5.1 fluid.
Ensure no air bubbles remain in the system before sealing and cleaning excess fluid. Remove the bleed block and insert the rotor spacer before re-installing the wheel.
Pairing and Configuring the AXS System
Hold the AXS buttons on each lever until the LED blinks rapidly. Repeat on the rear derailleur and press the pairing button on the derailleur. All components should sync automatically. Test shift function and confirm derailleur alignment using the SRAM AXS app for micro-adjustments.
Caliper Alignment and Rotor Rub Prevention
Spin the wheel and loosen caliper bolts slightly. Squeeze the brake lever firmly and hold it while re-torquing bolts to 6 Nm. This centers the caliper over the rotor to minimize rubbing. Repeat for both wheels and verify lever feel.
Post-Installation Pad Bedding
To bed in new brake pads, accelerate the bike to 15–20 km/h and brake firmly 20 times. Allow the rotors to cool slightly between applications. This process ensures optimal brake modulation and prevents rotor glazing.
Troubleshooting Common Installation Issues
Soft Lever Feel
Indicates air in the hydraulic system. Re-bleed using the Bleeding Edge tool and verify no fluid leaks exist.
Rotor Rubbing After Caliper Alignment
May be caused by warped rotors or misaligned mounts. Use a rotor truing tool and inspect flat-mount adapter compatibility.
Brake Squawk or Noise
Often due to contaminated pads or rotors. Clean rotors with isopropyl alcohol and sand pads lightly, or replace if heavily soiled.
Unresponsive Lever Movement
Could point to improperly connected hydraulic lines or insufficient fluid. Double-check hose engagement and fluid levels.
Customization and Performance Optimization
The Force eTap AXS D2 HRD allows riders to customize lever paddle functions using the SRAM AXS app. Riders can assign up/downshift behaviors to either paddle, fine-tune pad contact using reach adjustment screws under the hoods, and match lever shape to hand ergonomics.
For gravel racing, consider using CenterLine XR rotors to reduce weight and enhance airflow for better heat dissipation. Pair with organic pads for quieter operation or metallic pads for longer-lasting performance in muddy conditions.
Compatibility with Other Drivetrain Components
The Force eTap AXS D2 HRD system is compatible with any AXS-series derailleur, including Red, Force, and Rival eTap models. Chainring and cassette compatibility depends on chain width and tooth profiles. Ensure use of SRAM’s Flattop chain with 12-speed AXS components and match cassettes to XDR driver bodies.
Hydraulic brake calipers use standard SRAM pads and are backward compatible with most flat-mount road frames. Ensure hose fitting compatibility when mixing components across generations.
Comparing SRAM Force eTap AXS D2 HRD with Rival and Red
Compared to SRAM Rival eTap AXS HRD [paid link], the Force version offers carbon levers, lower weight, and improved tactile feedback. While Red eTap AXS is lighter and more refined, Force D2 brings significant improvements in ergonomics and shifting logic at a more approachable price point, making it ideal for gravel riders seeking race-capable performance.
Force D2 also features refined hood shaping, enhanced lever texture, and more customizable tactile feedback, placing it closer to Red than Rival in real-world use.
Maintenance Schedule and Best Practices
Inspect pad wear every 500 km or monthly for frequent riders. Clean rotors weekly to avoid build-up. Re-bleed brakes every 6–12 months depending on use intensity. Replace hoses every 18–24 months or when signs of cracking or softness appear.
For long-distance gravel events, carry a spare set of pads and a bleed block. Periodically check lever reach settings and recalibrate AXS shifting through the app as firmware updates are released.
Conclusion
Installing the SRAM Force eTap AXS D2 HRD brake set on a gravel bike is a highly rewarding project when executed with precision. From hydraulic setup to wireless pairing and rotor alignment, every step contributes to achieving peak braking performance and shifting efficiency. Proper customization, frequent inspection, and smart troubleshooting ensure this advanced system delivers on its promise of top-tier gravel performance.