1. Introduction
This manual provides detailed instructions for the installation, operation, maintenance, and troubleshooting of your microSHIFT R8 Rear Derailleur. The R8 Rear Derailleur is designed for 8 and 9-speed road bike systems, offering precise and reliable gear changes. Constructed with durable composite and steel components, this short cage derailleur is optimized for double chainring setups with a maximum sprocket size of 28T and a chain wrap capacity of up to 33 teeth.
Figure 1: The microSHIFT R8 Rear Derailleur. This image shows the black, short-cage derailleur with its pulley wheels and mounting bolt, designed for road bike applications.
2. Setup
2.1. Installation
- Prepare the Frame: Ensure the derailleur hanger is straight and clean. A bent hanger can cause poor shifting performance.
- Attach the Derailleur: Thread the derailleur's mounting bolt into the derailleur hanger. Tighten to the manufacturer's specified torque (typically 8-10 Nm), ensuring the B-tension screw rests against the hanger tab.
- Install the Chain: Route the chain through the derailleur cage, ensuring it passes correctly over the guide and tension pulleys.
- Connect the Cable: Route the shift cable from the shifter to the derailleur. Secure the cable to the derailleur's cable anchor bolt, ensuring there is no slack.
2.2. Initial Adjustment
- High Limit Screw (H): With the chain on the smallest rear cog, adjust the 'H' screw so the guide pulley is directly aligned with the smallest cog. This prevents the chain from shifting off the cassette into the frame.
- Low Limit Screw (L): With the chain on the largest rear cog, adjust the 'L' screw so the guide pulley is directly aligned with the largest cog. This prevents the chain from shifting off the cassette into the spokes.
- B-Tension Screw: With the chain on the largest rear cog and the largest front chainring, adjust the B-tension screw to set the gap between the guide pulley and the largest cog. Aim for a gap of 5-7mm. This optimizes shifting performance and reduces noise.
- Cable Tension: Shift to the second smallest cog. Use the barrel adjuster on the derailleur (or shifter) to fine-tune cable tension. Turn clockwise to move the derailleur inward (towards larger cogs) and counter-clockwise to move it outward (towards smaller cogs). Adjust until shifting is smooth and precise across all gears.
3. Operating
The microSHIFT R8 Rear Derailleur operates in conjunction with your 8 or 9-speed road shifters. To shift to a larger cog (easier gear), actuate your shifter to pull more cable, moving the derailleur inward. To shift to a smaller cog (harder gear), actuate your shifter to release cable, allowing the derailleur to move outward. Always shift while pedaling with moderate pressure; avoid shifting under heavy load or when stationary to prevent damage and ensure smooth transitions.
4. Maintenance
- Cleaning: Regularly clean the derailleur, especially the pulleys and cage, to remove dirt, grime, and old lubricant. Use a degreaser and a brush, then rinse thoroughly.
- Lubrication: After cleaning, apply a light bicycle-specific lubricant to the pivot points of the derailleur and the pulley bearings. Avoid over-lubricating, as this can attract more dirt.
- Inspection: Periodically check the derailleur for signs of wear or damage, such as bent cage plates, worn pulley teeth, or loose bolts. Ensure the cable is free of fraying and the housing is not kinked.
- Cable and Housing: Replace shift cables and housing annually or whenever shifting performance degrades significantly, as friction in the cable system can severely impact shifting.
5. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Slow or Hesitant Shifting | Insufficient cable tension, dirty cable/housing, bent derailleur hanger. | Increase cable tension with barrel adjuster, clean/replace cable and housing, check/straighten derailleur hanger. |
| Chain Rubs on Derailleur Cage | Incorrect limit screw adjustment, bent cage. | Adjust 'H' or 'L' limit screws, inspect and replace if cage is bent. |
| Chain Jumps Off Smallest Cog | 'H' limit screw set too far out. | Turn 'H' limit screw clockwise until the chain aligns with the smallest cog. |
| Chain Jumps Off Largest Cog into Spokes | 'L' limit screw set too far out. | Turn 'L' limit screw clockwise until the chain aligns with the largest cog. |
| Noisy Operation | Incorrect B-tension, dirty pulleys, worn chain/cassette. | Adjust B-tension, clean/lubricate pulleys, inspect and replace worn drivetrain components. |
6. Specifications
| Model Name | R8 Rear Derailleur |
| Part Number | RD-R32S |
| Compatibility | 8 and 9-speed road shifters |
| Cage Length | Short Cage |
| Maximum Sprocket Size | 28T |
| Chain Wrap Capacity | 33 teeth |
| Material | Composite and Steel |
| Color | Black |
| Item Weight | 0.71 Pounds (approx. 322 grams) |
| Product Dimensions | 9"L x 5.5"W x 1"H |
| Mounting Type | Braze-On Mount |
Note: Specifications are subject to change without notice.
7. Warranty
The microSHIFT R8 Rear Derailleur comes with a Limited Warranty. For specific terms, conditions, and duration of the warranty, please refer to the official microSHIFT warranty policy documentation provided with your purchase or visit the official microSHIFT website. This warranty typically covers manufacturing defects and material flaws under normal use.
8. Support
If you encounter issues that cannot be resolved using the troubleshooting guide, or if you require professional assistance, it is recommended to consult a qualified bicycle mechanic. For further technical support or inquiries regarding your microSHIFT R8 Rear Derailleur, please visit the official microSHIFT website or contact their customer service department.
