Why Your Shimano CN-6701 Chain Might Not Be Set Up Correctly and How to Fix It

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The Shimano CN-6701 [paid link] chain is a high-performance 10-speed road chain designed for precise shifting and efficient power transfer. However, even the most advanced chains can underperform if not installed or set up correctly. Improper chain configuration can lead to poor shifting, drivetrain noise, and accelerated component wear. This guide explores the most frequent set-up mistakes with the CN-6701 [paid link] and offers step-by-step fixes to restore peak performance.

Understanding the Shimano CN-6701 Chain

The CN-6701 [paid link] is part of Shimano’s Ultegra 6700 series. It features an asymmetric design optimized for smoother front and rear shifting. Unlike symmetrical chains, the CN-6701 has an outer and inner plate orientation that must be correctly aligned to function properly. Installing this chain incorrectly can significantly impair drivetrain efficiency.

Improper Chain Direction: A Critical Setup Flaw

One of the most overlooked errors is installing the chain in the wrong direction. The CN-6701 has a directional design that only works efficiently when the outer plates face outward (visible side) and the inner plates face inward (toward the bike frame).

When the chain is installed backwards:

  • Shifting becomes sluggish, especially on the front derailleur.
  • Increased chain noise occurs under load.
  • Wear accelerates on the cassette and chainrings.

To fix this, remove the chain, flip it, and reinstall it with the correct orientation. Always refer to Shimano’s directional marking near the chain’s outer plate to confirm proper installation.

Incorrect Chain Length: Why It Matters

Chain length directly affects shifting quality and drivetrain tension. A chain that’s too short can restrict gear range and risk drivetrain damage, while a chain that’s too long may cause slack and poor tension, especially on smaller cogs.

To verify correct length:

  • Wrap the chain around the largest chainring and largest cassette cog (without routing through the derailleur).
  • Add two full links (one inner and one outer plate) to determine ideal length.

If your CN-6701 chain is already installed, inspect for excess slack or overly tight derailleur tension. Adjust by breaking the chain at the quick-link or pin and resizing accordingly.

Inadequate Chain Tension and Derailleur Compatibility

Even with the right chain length, improper tension can arise from a misaligned derailleur or worn-out tension springs. Shimano designed the CN-6701 to pair with Ultegra 6700-series derailleurs, which have specific capacity ranges. Using an incompatible derailleur may result in:

  • Insufficient chain take-up.
  • Chain rubbing or slack when cross-chaining.
  • Inconsistent shifting on the cassette.

Check that your derailleur is rated for a 10-speed system and falls within the total capacity needed for your front and rear gear range. If not, consider upgrading to a compatible model for reliable chain tension management.

Misaligned Chainline and Front Shifting Performance

An improper chainline—the alignment of the chain between chainrings and cassette—can severely hinder front shifting, especially on double or compact cranksets. The CN-6701 is optimized for standard Shimano cranksets with a chainline around 43.5 mm.

A chainline that deviates too far from this standard can cause:

  • Chain drop on inner or outer chainrings.
  • Noisy operation in small-to-small or big-to-big gear combinations.
  • Premature wear on chainring teeth.

Correcting the chainline may involve adjusting bottom bracket spacers or ensuring the crankset is properly torqued and seated. Consult your frame and component specs to fine-tune the setup.

Lubrication Oversights Impacting Chain Setup

Inadequate or inappropriate lubrication not only affects performance but can also give the false impression of a set-up issue. The CN-6701 requires regular cleaning and proper lube application for optimal function.

Dry or contaminated chains may mimic:

  • Shifting hesitation.
  • Chain skipping or skidding under load.
  • Grinding noises during pedaling.

Use a high-quality, drivetrain-specific lubricant and clean the chain thoroughly before application. Over-lubrication should also be avoided, as it attracts dirt and exacerbates wear.