The Shimano Ultegra FD-6700 [paid link] front derailleur is a precise and durable component, designed to deliver smooth shifting across double chainrings. However, like any mechanical part, it requires proper installation, adjustment, and maintenance to function correctly. Riders often encounter recurring issues that can compromise performance. This guide examines the most common problems with the FD-6700 [paid link] front derailleur and provides clear solutions to restore reliable shifting.
Poor Shifting Between Chainrings
One of the most frequent issues with the FD-6700 [paid link] is sluggish or incomplete shifting between the small and large chainrings. This usually stems from cable tension that is either too loose or too tight. Insufficient tension prevents the derailleur from moving far enough to engage the big ring, while excessive tension can cause overshifting. Correcting this involves fine-tuning cable tension with the barrel adjuster until the derailleur consistently moves the chain across both rings with minimal hesitation.
Chain Rub on the Front Derailleur Cage
Another common problem is chain rub on the inner or outer cage plates. This occurs when the derailleur is not properly aligned with the chainrings or when the trim adjustment has not been set correctly. Riders often hear a persistent noise in certain gear combinations. To fix this, the derailleur cage must be positioned parallel to the chainrings and set at the proper height above the largest chainring. Fine adjustments to the limit screws will help eliminate rubbing across the full gear range.
Incorrect Limit Screw Adjustment
Improper limit screw adjustment is a source of multiple issues. If the high limit screw is set too tight, the chain may fail to shift onto the large chainring. If it is too loose, overshifting and chain drop to the outside can occur. Similarly, a poorly set low limit screw can cause chain drop onto the bottom bracket shell or prevent the chain from engaging the small chainring. The solution is to carefully reset both limit screws, ensuring the derailleur stops precisely at the edge of each chainring without forcing the chain beyond.
Cable Friction and Stiff Operation
Over time, shift cables can corrode, fray, or develop friction inside the housing, leading to heavy lever feel and delayed derailleur response. On the FD-6700, this manifests as sluggish front shifts or the derailleur failing to return to its resting position. Replacing the cable and housing with high-quality, lubricated parts restores crisp shifting and reduces lever resistance. Regular inspection and replacement are essential for long-term reliability.
Derailleur Cage Deformation
In some cases, the derailleur cage can become bent or twisted due to a crash, impact, or excessive force during shifting. A misaligned cage disrupts the chainline and prevents precise gear changes. If the deformation is minor, careful realignment may restore functionality, but in most cases, replacing the derailleur is the best option to guarantee accuracy.
Noise and Vibration Under Load
The FD-6700 can sometimes generate noise under high pedaling torque, even when shifting is otherwise functional. This is often caused by insufficient tightening of the derailleur clamp bolt or a mismatch between the derailleur and chainring profiles. Ensuring that the clamp is secure and that the derailleur is compatible with the crankset configuration reduces vibration and eliminates most noise-related issues.
Compatibility-Related Problems
Although the FD-6700 was designed for use with Shimano Ultegra 10-speed drivetrains, some riders attempt to pair it with mismatched components. Using it with modern 11-speed systems, or with non-Shimano cranksets, can lead to poor shifting due to differences in chainline and chainring spacing. Ensuring compatibility with the correct chainrings, shifters, and chain is crucial for maintaining consistent performance.
Cable Anchor Bolt Slippage
If the cable anchor bolt is not torqued correctly, the cable may slip under load, causing a sudden loss of shifting precision. This results in the derailleur failing to reach the intended gear. Retightening the anchor bolt to the manufacturer’s torque specification resolves the issue and prevents recurrence.
Premature Wear of the Derailleur Mechanism
After extended use, the pivot points of the FD-6700 can wear, leading to play in the derailleur body and imprecise shifting. Lack of lubrication accelerates this process. Applying a light lubricant to the pivots and regularly cleaning the derailleur helps maintain smooth operation. In severe cases of wear, replacement is necessary to restore shifting accuracy.
Chain Drop During Shifts
Chain drop, whether to the inside or outside, is a frustrating problem. This usually results from a combination of poor limit screw adjustment, cable tension errors, and worn chainrings. Correctly setting the derailleur limits, keeping chainrings in good condition, and ensuring the derailleur height is optimal will minimize the risk of dropping the chain.
Conclusion
The Shimano Ultegra FD-6700 front derailleur is a reliable and precise component when properly set up and maintained. Most shifting problems arise from incorrect installation, poor adjustment, or worn parts. By addressing issues such as cable tension, limit screw settings, cage alignment, and compatibility, riders can restore smooth shifting and extend the service life of the derailleur. Regular inspection, cleaning, and lubrication ensure the FD-6700 continues to deliver the performance expected from Shimano’s Ultegra series.