The Shimano FD-6700 [paid link] front derailleur, part of the Ultegra 6700 series, is designed for precise and smooth shifting performance when paired with the correct drivetrain components. However, even small errors in installation or adjustment can lead to poor performance, chain rub, or missed shifts. Understanding why your FD-6700 [paid link] might not be set up correctly is essential for restoring reliable function. This guide explores common mistakes, the technical reasons behind them, and the steps required to correct the set-up.
Understanding the FD-6700 Front Derailleur
The FD-6700 [paid link] is a braze-on or clamp-style front derailleur engineered for use with Shimano 10-speed drivetrains. It features a wide inner link design for stiffness, an optimized cage shape for compact or standard chainring combinations, and compatibility with Shimano’s Ultegra STI shifters. Because of its precise tolerances, even small errors in height, angle, or cable tension can affect performance.
Common Reasons the FD-6700 Feels Incorrect
Incorrect Mounting Height
If the derailleur cage sits too high above the large chainring, shifts will feel sluggish and may require extra lever force. If set too low, the cage will rub against the teeth of the chainring. Shimano specifies that the outer cage plate should sit 1–3 mm above the tallest tooth on the large chainring.
Improper Cage Alignment
The cage must be parallel to the chainrings. If it is rotated inward or outward, the chain will rub on the plates during gear changes. This issue often appears as noise when shifting into the big ring or difficulty when moving from the small to the large chainring.
Cable Tension Errors
The FD-6700 relies on correct cable tension for smooth actuation. Too little tension results in hesitation when shifting to the big chainring, while too much tension can cause overshifting or difficulty dropping to the small ring.
Limit Screw Misadjustment
The derailleur’s limit screws prevent the cage from moving too far inward or outward. If the low limit is set too tight, the chain may not climb onto the big ring. If the high limit is misadjusted, the chain may overshift and drop. Both must be carefully tuned to match the chainline.
Chainline and Bottom Bracket Issues
The FD-6700 is designed around a specific chainline (43.5 mm for standard Shimano road setups). If the bottom bracket spacing is incorrect or non-standard chainsets are used, the derailleur may not track correctly. This can cause persistent rub or difficulty accessing all gears.
How to Correct a Poor FD-6700 Set-Up
Step 1: Check Mounting Height
Loosen the derailleur clamp bolt and align the outer cage plate so it sits 1–3 mm above the tallest chainring tooth. Retighten the clamp securely while holding the derailleur in position.
Step 2: Align the Cage
Ensure the cage is perfectly parallel to the chainrings. Small deviations create noise and poor shifts. Adjust carefully before tightening the clamp.
Step 3: Set the Low Limit Screw
Shift the chain onto the small chainring and largest rear cog. Adjust the low limit screw so the inner cage plate clears the chain by 0.5 mm without rubbing.
Step 4: Adjust Cable Tension
Attach the cable and pull it tight, ensuring the pinch bolt is secure. Use the barrel adjuster on the downtube or shifter to fine-tune tension. The derailleur should move cleanly from small to large chainring with a single lever push.
Step 5: Set the High Limit Screw
Shift to the large chainring and smallest rear cog. Adjust the high limit screw so the outer cage plate sits just clear of the chain, preventing overshift while allowing full engagement.
Step 6: Verify Chainline and Compatibility
Ensure the crankset and bottom bracket match Shimano’s specifications. Non-standard parts can affect derailleur position, making precise adjustment impossible.
Symptoms of a Misaligned FD-6700 and Their Fixes
- Chain rub in large chainring, small cog: High limit screw too loose or cage angled outward.
- Difficulty shifting to big chainring: Cable tension too low or cage too high.
- Overshifting off big ring: High limit screw too loose.
- Noise in small chainring, large cog: Low limit screw too tight or cage angled inward.
- General sluggish shifting: Combination of cable friction, poor alignment, or worn cables and housing.
Final Thoughts
The Shimano FD-6700 front derailleur is highly capable when installed and adjusted to specification. Most performance issues arise from small errors in cage height, angle, or limit screw settings. By systematically checking each adjustment point and ensuring proper compatibility, you can restore crisp and reliable shifting. Careful set-up ensures that your FD-6700 functions as Shimano intended, delivering the smooth gear changes required for confident road cycling.