1. Introduction
The TRP HD-C705 and HD-C711 are high-performance cable-actuated hydraulic disc brake calipers designed for cyclocross (CX) and road bikes. These innovative brakes combine the ease of integration with existing cable-pull levers with the superior power and modulation of a hydraulic braking system. Featuring an open hydraulic system and a dual-piston design, they offer consistent and reliable stopping power in various conditions. The system utilizes mineral oil for optimal performance and durability.
The HY/RD system has been recognized with prestigious awards, including the German iF Industrial Design Award and the Red Dot Design Award 2013, highlighting its innovative design and engineering excellence.
2. Setup and Installation
This section provides general guidelines for installing your TRP HD-C705 or HD-C711 brake caliper. Professional installation by a qualified bicycle mechanic is recommended.
2.1 Caliper Mounting
- HD-C705 (Post Mount): This model is designed for frames and forks with post mount tabs. Ensure proper adapter (if needed) and bolt length are used for secure attachment.
- HD-C711 (Flat Mount): This model is designed for frames and forks with flat mount tabs, commonly found on modern road and CX bikes. Ensure correct bolt length and washers are used.
2.2 Cable Connection and Adjustment
- Route your existing brake cable from the lever to the caliper.
- Secure the brake cable into the caliper's cable anchor bolt.
- Important: When adjusting the brake cable tension, ensure the locking screw adjustment knob on the caliper is engaged (locked). This prevents the piston within the hydraulic cylinder from moving out of its initial set position during cable tensioning, ensuring proper brake function.
- Adjust cable tension to achieve the desired lever feel and brake pad clearance.
- Ensure the brake pads are properly aligned with the rotor and do not rub when the brake is disengaged.
- Tighten all bolts to the manufacturer's recommended torque specifications.
3. Operating Your Brakes
The TRP HY/RD system is designed to provide powerful and controlled braking. Once installed and properly adjusted, operate the brakes by pulling your existing mechanical brake levers. The hydraulic mechanism within the caliper will translate this cable pull into hydraulic pressure, engaging the dual pistons to clamp the rotor.
- Braking Feel: Expect a firm and consistent lever feel, offering excellent modulation for precise speed control.
- Bedding-in: New brake pads and rotors require a 'bedding-in' period to achieve full braking power. Perform several moderate stops from a cruising speed to allow the pads to conform to the rotor surface.
4. Maintenance
Regular maintenance ensures the longevity and optimal performance of your TRP HY/RD brakes.
4.1 General Inspection
- Periodically check brake pads for wear and replace them when necessary.
- Inspect the brake rotor for damage, excessive wear, or contamination.
- Ensure all mounting bolts are securely tightened.
- Check brake cables for fraying or corrosion and replace as needed.
4.2 Hydraulic System
The HY/RD system features a mineral oil reservoir. This reservoir is designed for strong sealing, is made from durable aluminum alloy, and has a large oil storage capacity to ensure consistent performance.
- Only use TRP-approved mineral oil for any fluid maintenance.
- If the brake lever feels spongy or braking power diminishes significantly, the system may require bleeding. This is a specialized procedure and should be performed by a qualified mechanic.
- Do not use DOT fluid, as this will damage the seals and void your warranty.
5. Troubleshooting
Below are some common issues and potential solutions for your TRP HY/RD brakes.
| Problem | Possible Cause | Solution |
|---|---|---|
| Spongy lever feel | Air in the hydraulic system, worn cable, improper cable tension. | Check cable tension and condition. If issue persists, the system may need bleeding by a professional. |
| Reduced braking power | Worn brake pads, contaminated pads/rotor, improper bedding-in, air in system. | Inspect and replace pads if worn. Clean rotor and pads (if contaminated). Re-bed brakes. Consider professional bleeding. |
| Brake rub | Misaligned caliper, bent rotor, sticky piston. | Realign caliper. Check rotor for trueness. Consult a mechanic for sticky pistons. |
For complex issues or if you are unsure about any repair, please consult a certified bicycle mechanic.
6. Specifications
| Feature | Detail |
|---|---|
| Model Numbers | HD-C705 (Post Mount), HD-C711 (Flat Mount) |
| Braking System | Cable Actuated Hydraulic Disc Brake (Hydraulic Brake Pad) |
| Material | Aluminum Alloy |
| Weight (HD-C705 Post Mount) | Approximately 250g per caliper |
| Weight (HD-C711 Flat Mount) | Approximately 224g per caliper |
| Hydraulic Fluid | Mineral Oil |
| Origin | Taiwan (China) |
| Packaging | One caliper per box |
7. User Tips
- Single Unit Packaging: Please note that these calipers are typically sold individually (one caliper per box). If you require brakes for both front and rear wheels, you will need to purchase two units.
- Cable Tension Adjustment: Always remember to engage the locking screw adjustment knob when setting your cable tension. This critical step prevents internal piston movement and ensures correct brake setup.
- Rotor Compatibility: Ensure your rotors are compatible with resin/organic pads, as these are typically supplied with the calipers.
8. Warranty and Support
For warranty claims, technical support, or service inquiries, please contact your original point of purchase or the official TRP Cycling Components distributor in your region. Keep your proof of purchase for any warranty-related matters.