How to Install, Adjust, and Maintain the Shimano RD-6770 Rear Derailleur

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in Rear Derailleur, Shimano, Ultegra

The Shimano RD-6770 [paid link] rear derailleur is part of Shimano’s first-generation Di2 electronic shifting system, designed for precise, effortless gear changes in road cycling. As an electronic derailleur, the RD-6770 [paid link] eliminates traditional cable friction issues and ensures consistent shifting performance under various riding conditions.

In this guide, we’ll cover everything you need to know about the RD-6770 [paid link], including installation, adjustment, maintenance, and troubleshooting tips to keep your shifting smooth and reliable.

Tools Required [paid links]

To install and maintain the RD-6770, you’ll need:

  • Allen keys
  • Torque wrench (for precise tightening)
  • Shimano Di2 PC linkage device (SM-PCE1 or SM-PCE02)
  • E-Tube project software (for firmware updates and diagnostics)
  • Chain tool
  • Phillips screwdriver
  • Isopropyl alcohol (for cleaning contacts)
  • Soft-bristle brush and degreaser

Understanding the Shimano RD-6770 Rear Derailleur

The RD-6770 is an 11-speed Di2 rear derailleur that operates electronically via Shimano’s E-Tube system. Unlike mechanical derailleurs, it relies on a small servo motor to move the derailleur precisely based on shifting inputs.

Key Features of the RD-6770:

  • Electronic Shifting: Provides fast and accurate gear changes with minimal effort.
  • E-Tube Compatibility: Allows for firmware updates and fine-tuning through Shimano’s software.
  • Automatic Trim: Reduces chain rub by adjusting the front derailleur automatically.
  • Lightweight Alloy Construction: Durable yet optimized for weight savings.
  • 11-Speed Cassette Compatibility: Works with Shimano’s 11-speed road groupsets.

Step-by-Step Installation of the Shimano RD-6770

1. Preparing the Bike

  • Secure the bike on a stand to ensure easy access.
  • Check derailleur hanger alignment using a derailleur hanger alignment tool. A misaligned hanger can cause shifting issues even with electronic shifting.
  • Ensure all E-Tube wires are intact and properly routed.

2. Mounting the Rear Derailleur

  • Attach the RD-6770 to the derailleur hanger using a 5mm Allen wrench [paid link].
  • Tighten the mounting bolt to 8-10 Nm torque to prevent overtightening or loosening.
  • Ensure the B-tension adjustment screw is in an optimal position to provide proper chain wrap around the cassette.

3. Connecting the Di2 System

  • Plug the E-Tube wire into the RD-6770’s port until it clicks into place.
  • Connect the wire to the junction box (SM-JC40 [paid link] or SM-JC41 [paid link]), ensuring all connections are secure.
  • If installing a new Di2 system, connect the battery (SM-BTR1 or SM-BTR2) and ensure it is fully charged.

4. Setting the Chain and Cassette

  • Install a compatible 11-speed Shimano cassette.
  • Set the chain length using Shimano’s chain length guide, ensuring it wraps properly around the largest rear cog and front chainring.
  • Use a quick link or Shimano pin to secure the chain.

Adjusting the RD-6770 Rear Derailleur for Optimal Performance

Once installed, proper adjustment ensures smooth shifting and longevity of the derailleur.

1. Aligning the Derailleur with the Cassette

  • Shift to the smallest cog and check if the derailleur sits directly in line with it.
  • If necessary, adjust the high-limit screw until the jockey wheel aligns perfectly.

2. Setting the Low Limit Screw

  • Shift to the largest cog and ensure the jockey wheel aligns with it.
  • Turn the low-limit screw to fine-tune alignment and prevent over-shifting into the spokes.

3. B-Tension Adjustment

  • Adjust the B-tension screw so that the upper jockey wheel maintains an optimal gap (5-6mm) from the largest cog.
  • This prevents excessive chain wrap issues and ensures smooth shifting.

4. Fine-Tuning via E-Tube Software

  • Connect the SM-PCE1 or SM-PCE02 diagnostic tool to the Di2 system.
  • Open E-Tube Project software and perform a gear index adjustment for precise shifting.
  • Apply micro-adjustments if necessary for seamless transitions between gears.

Maintenance Plan for the Shimano RD-6770

Regular maintenance keeps your Di2 rear derailleur performing at its best.

1. Cleaning the Derailleur

  • Use a soft brush and degreaser to remove dirt from the derailleur body and jockey wheels.
  • Wipe down with a clean rag and apply a light lubricant to the pivots.
  • Avoid excess lubrication, as this can attract dirt and grime.

2. Checking the Battery and Wiring

  • Charge the Di2 battery regularly to prevent shifting failure.
  • Inspect E-Tube wires for any wear or damage.
  • Use isopropyl alcohol to clean wire connections for a stable electronic signal.

3. Updating Firmware and Diagnostics

  • Connect the Di2 system to Shimano’s E-Tube software at least once every few months.
  • Check for firmware updates that improve shifting accuracy and component compatibility.
  • Run diagnostics to detect any hidden issues before they become serious.

Troubleshooting Common RD-6770 Issues

1. Slow or Unresponsive Shifting

  • Ensure the battery is fully charged.
  • Check E-Tube connections for loose or corroded wires.
  • Run a gear index adjustment through E-Tube Project software.

2. Noisy Shifting or Chain Skipping

  • Inspect the chain for wear and replace it if necessary.
  • Verify cassette wear, as a worn-out cassette can cause inconsistent shifting.
  • Adjust the B-tension screw to optimize the upper jockey wheel position.

3. Over-Shifting or Auto-Correcting Issues

  • Reset the Di2 system by holding the shift button for 5 seconds.
  • Perform a micro-adjustment via E-Tube software.

Conclusion

The Shimano RD-6770 Di2 rear derailleur is a precision-engineered component that provides seamless electronic shifting for road cyclists. By following the correct installation, adjustment, and maintenance steps, you can ensure peak performance and longevity from your Di2 system.