How to Adjust the Shimano CN-HG701 Chain Length: A Complete Guide

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The Shimano CN-HG701 [paid link] chain is a popular choice among road cyclists seeking reliable, smooth-shifting performance. However, achieving optimal performance depends heavily on setting the correct chain length. Incorrect chain length can lead to poor shifting, premature wear, and drivetrain inefficiency. In this comprehensive guide, you will learn how to properly adjust the CN-HG701 [paid link] chain length to ensure peak operation and longevity.

Tools Required

  • Chain tool (compatible with 11-speed chains)
  • Master link pliers (if using Shimano’s Quick-Link)
  • Chain checker gauge
  • Tape measure or ruler
  • Gloves
  • Chain wear indicator (optional)

Understanding the Importance of Correct Chain Length

The Shimano CN-HG701 [paid link] chain is engineered for 11-speed drivetrains, designed to provide optimal contact with cassette and chainring teeth. Chain length affects tension, shifting precision, and overall drivetrain efficiency. Too short a chain can stress the derailleur and chainrings, while too long a chain leads to chain slap and poor engagement.

Correct chain length ensures:

  • Smooth and accurate shifting
  • Proper derailleur positioning
  • Extended drivetrain lifespan
  • Efficient power transfer

Measuring Chain Length: The Standard Method

When adjusting the Shimano CN-HG701, use the “big-big” method—routing the chain around the largest chainring and the largest cassette sprocket without passing through the rear derailleur.

Steps:

  1. Shift the front derailleur onto the largest chainring and the rear derailleur onto the largest sprocket.
  2. Route the new chain around both, bypassing the rear derailleur.
  3. Pull both ends tight to eliminate slack.
  4. Add two full links (one inner and one outer plate) to the chain.
  5. Mark this point for cutting.

This method ensures the chain accommodates the full range of gearing without overextending the rear derailleur, critical for avoiding drivetrain damage.

Determining Chain Length for Full Suspension Bikes

For full suspension frames, chainstay length changes as the suspension compresses. In these cases, it is crucial to allow extra slack. Follow the manufacturer’s guidelines or consult a bike-specific fitting chart. A common practice is to add an additional half-link of slack beyond the standard “big-big” method for suspension travel accommodation.

Using the Existing Chain as a Reference

If the original CN-HG701 chain was correctly sized and installed:

  1. Remove the old chain and lay it flat.
  2. Align the new chain next to the old one.
  3. Match the length precisely link-for-link.
  4. Cut the new chain accordingly.

Only use this method if you are certain the existing chain was correctly sized and hasn’t been stretched excessively.

Cutting the Shimano CN-HG701 Chain

Shimano chains must be cut carefully to preserve structural integrity. Always cut at the inner link to maintain compatibility with the connecting pin or Quick-Link.

Procedure:

  1. Place the chain in the chain tool, positioning the pin directly under the tool’s driving pin.
  2. Drive the pin out carefully to split the chain.
  3. Remove the excess links.
  4. Verify the ends are properly aligned and smooth.

Use Shimano’s Quick-Link (SM-CN900) for ease of connection, ensuring you do not reuse the connecting pin from a previous installation.

Final Installation and Connection

After cutting, install the chain onto the drivetrain, threading it through both derailleurs properly:

  • Ensure the chain passes over the top pulley (guide pulley) and under the bottom pulley (tension pulley) in the rear derailleur.
  • Check that the chain path is free from twists or misalignment.

Connect the chain ends using Shimano’s Quick-Link or a new Shimano connecting pin, depending on your preference. If using a Quick-Link:

  • Insert the link ends together.
  • Pull the crank arm sharply to snap the link into place.
  • Verify the link moves freely without binding.

If using the connecting pin:

  • Drive the new pin in using the chain tool.
  • Snap off the guide portion after installation.

Checking for Proper Chain Length and Tension

Once installed:

  • Shift through all gears to ensure smooth transitions.
  • In the smallest chainring and smallest sprocket combination, the derailleur should maintain enough tension to prevent the chain from sagging.
  • In the largest chainring and largest sprocket combination, the derailleur should not be stretched beyond its capacity, and the jockey wheels should remain vertically aligned.

A properly sized CN-HG701 chain will maintain smooth tension across all gears without excessive slack or stress.

Common Mistakes to Avoid

When adjusting the Shimano CN-HG701 chain length, avoid these common pitfalls:

  • Skipping the two-link rule: Not adding the extra two links can result in a chain that is too short.
  • Misrouting the chain: Incorrectly threading the chain through the derailleur cages leads to shifting issues.
  • Incorrect link cutting: Cutting on an outer plate link rather than an inner can complicate installation.
  • Reusing an old Quick-Link: Shimano Quick-Links are single-use; always use a new one for safety and performance.

Maintenance Tips for Optimal Chain Performance

After installation:

  • Regularly clean and lubricate the chain to prevent wear and corrosion.
  • Use a chain checker gauge every 500-1,000 km to monitor stretch and replace when needed.
  • Keep drivetrain components (chainrings, cassette, jockey wheels) clean to enhance chain life.

Conclusion

Properly adjusting the Shimano CN-HG701 chain length is a crucial step in ensuring smooth shifting, drivetrain longevity, and riding efficiency. Following the correct sizing methods and avoiding common mistakes will keep your bike running smoothly, mile after mile. Whether you’re a weekend enthusiast or a seasoned racer, attention to chain length details will make a significant difference in your cycling experience.