1. Introduction
This manual provides essential instructions for the proper installation, operation, and maintenance of your SHIMANO 105 ST-R7120-R Shift/Brake Lever and BR-R7170 Hydraulic Disc Brake Caliper. Please read this manual thoroughly before use to ensure safe and optimal performance of your cycling components.
Figure 1: SHIMANO 105 ST-R7120-R Shift/Brake Lever (left) and BR-R7170 Hydraulic Disc Brake Caliper (right). This image displays the complete set of the right-hand shift/brake lever and the corresponding hydraulic disc brake caliper, both in a black finish.
2. Safety Information
Always observe the following safety precautions to prevent personal injury and damage to your bicycle components.
- Ensure all components are installed correctly and securely tightened to the manufacturer's recommended torque specifications. Incorrect installation can lead to loss of control and serious injury.
- Regularly inspect brake pads for wear. Replace worn pads immediately to maintain effective braking performance.
- Check brake fluid levels and condition periodically. Use only SHIMANO genuine mineral oil for hydraulic brake systems.
- Do not modify any components. Unauthorized modifications can compromise safety and performance.
- Wear appropriate safety gear, including a helmet, when cycling.
- If you are unsure about any installation or maintenance procedure, consult a professional bicycle mechanic.
3. Package Contents
Verify that all items are present in your package:
- SHIMANO 105 ST-R7120-R Shift/Brake Lever (Right/Rear, 12-Speed)
- SHIMANO BR-R7170 Hydraulic Disc Brake Caliper (Flat Mount)
- Brake Pads (L05A-RF Resin with finned backplate)
- Hydraulic Brake Hose (pre-bled or requiring bleeding, depending on specific kit)
- Mounting Hardware (bolts, washers)
- User Manual (this document)
4. Setup and Installation
Proper installation is crucial for the performance and safety of your SHIMANO 105 components. If you lack experience, professional installation is recommended.
4.1. Shift/Brake Lever Installation (ST-R7120-R)
- Mounting to Handlebar: Position the ST-R7120-R lever on the right side of your drop handlebar. Ensure the lever is at an ergonomic angle that allows comfortable reach to both the brake lever and shift paddles. Tighten the clamp bolt to the specified torque.
- Reach Adjustment: The lever features customizable reach adjustment. Use a small hex key to adjust the lever position to suit your hand size and preference. Refer to the technical service instructions for detailed adjustment procedures.
- Cable Routing: Route the shift cable internally or externally according to your frame's design. Ensure smooth cable movement without kinks or excessive friction.
- Hydraulic Hose Connection: Connect the hydraulic brake hose from the caliper to the lever. Ensure a secure, leak-free connection. This may involve cutting the hose to length and installing olives and barbs.
4.2. Hydraulic Disc Brake Caliper Installation (BR-R7170)
- Mounting to Frame/Fork: The BR-R7170 is a flat mount caliper. Attach it to the designated flat mount points on your frame or fork using the provided mounting bolts. Ensure correct bolt length for your frame/fork thickness. Tighten to the specified torque.
- Rotor Clearance: The caliper offers 10% wider pad clearance, which helps reduce rotor rub. After mounting, ensure the brake rotor is centered within the caliper and does not rub against the pads when the brake is disengaged. Adjust caliper position if necessary.
- Pad Installation: The L05A-RF resin pads are pre-installed or can be easily inserted. Ensure the finned backplate is correctly oriented for heat dissipation.
4.3. Brake System Bleeding
After connecting the hydraulic hose, the brake system must be bled to remove any air and ensure proper function. SHIMANO's one-way bleeding system facilitates this process.
- Use SHIMANO genuine mineral oil and a SHIMANO bleeding kit.
- Follow the detailed instructions provided in the SHIMANO technical service manual for hydraulic disc brakes.
- Ensure no air bubbles remain in the system for consistent and powerful braking.
5. Operation
5.1. Shifting
The ST-R7120-R lever provides smooth and rapid 12-speed shifting for your rear derailleur.
- Upshifting (to a smaller cog/higher gear): Push the smaller lever blade inwards.
- Downshifting (to a larger cog/lower gear): Push the main brake lever blade inwards.
- Ensure smooth pedal rotation during shifting for optimal performance and to prevent chain stress.
5.2. Braking
The BR-R7170 hydraulic disc brake caliper, paired with the ST-R7120-R lever, delivers powerful and consistent stopping power.
- Gently squeeze the main brake lever blade to engage the brake. Apply pressure progressively for controlled deceleration.
- Avoid sudden, hard braking, especially in wet or loose conditions, to prevent skidding.
- Familiarize yourself with the brake feel and modulation before riding in challenging conditions.
6. Maintenance
Regular maintenance ensures the longevity and reliable performance of your SHIMANO 105 components.
6.1. Brake Pad Replacement
Inspect brake pads regularly for wear. Replace them when the pad material is worn down to the wear indicator line or if braking performance diminishes significantly.
- Remove the wheel.
- Remove the pad retaining pin and slide out the old pads.
- Gently push the caliper pistons back into their bores using a pad spreader tool.
- Insert new L05A-RF resin pads, ensuring the finned backplate is correctly positioned. Secure with the retaining pin.
- Reinstall the wheel and pump the brake lever several times to reset the pistons.
6.2. Brake System Inspection
- Check hydraulic hoses for any signs of damage, kinks, or leaks.
- Ensure all bolts are tightened to the correct torque specifications.
- Periodically check brake fluid for contamination or degradation. Bleed the system if necessary.
6.3. General Cleaning
Clean your components regularly with mild soap and water. Avoid high-pressure washing directly on seals or bearings. Lubricate moving parts of the shift mechanism as recommended by SHIMANO.
7. Troubleshooting
This section addresses common issues you might encounter.
| Problem | Possible Cause | Solution |
|---|---|---|
| Weak braking power | Air in hydraulic system, worn brake pads, contaminated rotor/pads. | Bleed the brake system. Replace worn pads. Clean rotor and pads with isopropyl alcohol. |
| Brake lever feels spongy | Air in hydraulic system. | Bleed the brake system thoroughly. |
| Rotor rub/noise | Caliper misalignment, bent rotor, sticky piston. | Realign caliper. True the rotor or replace if bent. Clean and lubricate pistons (consult professional). |
| Difficulty shifting | Cable friction, incorrect derailleur adjustment, bent hanger. | Check cable routing and tension. Adjust derailleur limits and B-tension. Inspect derailleur hanger. |
If you cannot resolve an issue using this guide, please contact SHIMANO customer support or a certified bicycle mechanic.
8. Specifications
| Feature | Detail |
|---|---|
| Model Numbers | ST-R7120-R (Shift/Brake Lever), BR-R7170 (Brake Caliper) |
| Brand | SHIMANO |
| Speed Compatibility | 12-Speed (Rear) |
| Brake Type | Hydraulic Disc Brake |
| Caliper Mount Type | Flat Mount |
| Brake Fluid | SHIMANO Mineral Oil |
| Brake Pads | L05A-RF Resin with finned backplate |
| Lever Material | Composite / Resin |
| Caliper Material | Aluminum |
| Hand Orientation | Right (for Rear Brake/Shifter) |
| Special Features | Enhanced ergonomic design, adjustable reach, 10% wider pad clearance, one-way bleeding. |
| Item Weight | Approximately 1.53 pounds (for the set) |
| Product Dimensions | 9.5 x 5 x 1 inches (packaging/overall) |
| ASIN | B0CKLKN6SW |
| UPC | 192790819143 |
9. Warranty and Support
SHIMANO products are manufactured to high standards and are covered by a limited warranty against defects in materials and workmanship. For specific warranty terms and conditions, please refer to the official SHIMANO website or contact your local SHIMANO distributor.
For technical support, spare parts, or further assistance, please visit the official SHIMANO website or contact their customer service department. Always provide your product model numbers (ST-R7120-R, BR-R7170) when seeking support.
