How to Replace the CS-6700 Cassette for Better Shifting and Performance

Replacing your Shimano CS-6700 [paid link] cassette is one of the most impactful ways to restore crisp shifting, improve drivetrain efficiency, and extend the life of your entire transmission system. Whether you’re experiencing inconsistent shifts, chain skipping, or general drivetrain sluggishness, installing a new cassette often brings a noticeable performance boost.

This article provides a detailed, model-specific guide on replacing the CS-6700 [paid link] cassette, ensuring compatibility, precise installation, and optimal adjustment.

Tools Required

Chain whip
Lockring removal tool (compatible with Shimano HG lockrings)
Adjustable wrench or torque wrench [paid link]
Cassette grease or anti-seize compound
Shop rag or brush for hub cleaning
Optional: Bike stand [paid link] for better access

Understanding the Shimano CS-6700 Cassette

The CS-6700 [paid link] is part of Shimano’s Ultegra 6700 groupset, designed for 10-speed drivetrains. Built with a refined gear progression and close-ratio spacing, it offers efficient cadence control for road cyclists. This model uses Hyperglide sprockets, optimized for seamless shifting under load.

The CS-6700 is available in a variety of gear ranges including 11-23T, 11-25T, 12-25T, and 11-28T. Each configuration uses a combination of individual cogs and pinned clusters to balance weight and performance. Understanding the configuration you currently use is crucial before replacing it.

When to Replace the CS-6700 Cassette

Visible signs of wear such as shark-toothed or heavily pitted teeth indicate it’s time for a replacement. However, performance issues like:

Sudden skipping under load
Poor gear transitions
Increased drivetrain noise
Chain wear despite recent replacement

also signal cassette degradation. Shimano recommends replacing the cassette approximately every 3,000 to 5,000 kilometers depending on riding conditions, chain maintenance, and rider weight.

Pre-Replacement Checklist

Before installing the new CS-6700 cassette:

Confirm drivetrain compatibility: Ensure your derailleur, shifter, and chain are compatible with a 10-speed cassette.
Inspect the freehub body: Look for gouging or burrs that might prevent proper cassette seating.
Check the chain for wear: A stretched chain can damage a new cassette prematurely. Replace it if necessary.

Step-by-Step Replacement Guide

Removing the Old Cassette

Begin by stabilizing your bike in a stand. Remove the rear wheel and lay it sprocket-side up. Using the chain whip to hold the cassette stationary, insert the lockring tool [paid link] into the center and loosen the lockring counterclockwise with your adjustable wrench.

Once removed, slide off each sprocket and spacer. Some higher cogs are riveted together as a cluster—remove them as a unit.

Cleaning the Freehub Body

Thoroughly wipe down the freehub body. Use a degreaser if necessary to remove old lubricant and debris. This ensures smooth cassette seating and minimizes creaking or misalignment.

Installing the New CS-6700 Cassette

Start by identifying the narrow spline on the freehub and align it with the matching slot on the cassette. Slide each sprocket and spacer onto the freehub in the correct order. Refer to the exploded view in Shimano’s technical documents if needed.

Once all sprockets are seated, thread on the lockring by hand, then torque it to Shimano’s recommended specification of 40 Nm using a torque wrench [paid link]. Do not overtighten, as this can damage the freehub threads.

Post-Installation Adjustments

After replacing the CS-6700 cassette:

Reinstall the wheel and check for secure seating in the dropouts.
Re-index the rear derailleur using the barrel adjuster. A new cassette may slightly alter the chainline, necessitating fine-tuning.
Shift through all gears under load to ensure smooth transitions.
Check for chain rub or misalignment. If shifting is inconsistent, adjust cable tension or B-tension screw.

Optimization Tips

For enhanced performance after installation:

Use a new Shimano 10-speed chain for best compatibility.
Avoid cross-chaining (e.g., large chainring to large cog) to reduce wear.
Keep the drivetrain clean and lubricated regularly.
Monitor cog wear periodically, especially if you often ride in wet or dusty environments.

Comparing Old vs. New Performance

Immediately after replacement, most riders notice:

Smoother, quieter gear changes
Reduced drivetrain resistance
Better cadence control, especially under power
Improved chain retention across all cogs

These improvements validate the replacement and demonstrate the importance of timely drivetrain maintenance.

FAQs About Replacing the Shimano CS-6700 Cassette

1. Can I use the CS-6700 cassette with an 11-speed chain?
No, it’s optimized for 10-speed chains. Using an 11-speed chain may lead to poor engagement and premature wear.

2. Do I need a new chain when replacing the cassette?
Yes, ideally. A worn chain can cause new cassette teeth to wear quickly or skip under load.

3. What gear range should I choose?
Match your riding terrain. Use 11-28T for climbing, 11-23T for flatter terrain and racing.

4. Is the CS-6700 compatible with a 105 or Dura-Ace 10-speed drivetrain?
Yes, all Shimano 10-speed road components are cross-compatible.

5. Can I install the CS-6700 on a mountain bike hub?
Only if it uses a Shimano 10-speed road-compatible freehub. Most MTB hubs are not compatible.

6. How long does the CS-6700 cassette last?
With proper maintenance, it can last 3,000–5,000 km. Harsh conditions may shorten this lifespan.

Conclusion

Replacing your Shimano CS-6700 cassette is a straightforward yet highly beneficial upgrade that significantly enhances drivetrain performance. Whether you’re restoring shifting precision or refreshing worn components, this guide ensures a successful, model-specific installation. By understanding compatibility, following precise installation steps, and tuning your drivetrain post-installation, you’ll enjoy smoother, more efficient rides across varied terrains.