The Shimano CS-6700 [paid link] cassette, part of the Ultegra 6700 groupset, is a finely tuned component designed for performance road cycling. However, even high-end cassettes like the CS-6700 [paid link] are vulnerable to user error. Whether you’re a seasoned mechanic or a new enthusiast, avoiding common pitfalls during installation and maintenance is crucial for drivetrain longevity and smooth shifting. This guide highlights the most damaging mistakes riders make with the CS-6700 [paid link] and offers corrective strategies to keep your drivetrain performing at its best.
Improper Cassette Installation and Lockring Torque
One of the most frequently overlooked aspects of installing the CS-6700 is securing the cassette with the correct torque. The lockring must be tightened to Shimano’s recommended torque specification—typically around 40 Nm. Failing to meet this torque spec can lead to cassette wobble under load, premature wear of the freehub splines, and inconsistent gear engagement.
In contrast, overtightening the lockring can damage the threads on the freehub body or deform the aluminum carriers of the cassette, both of which are costly to repair. Always use a torque wrench [paid link] to confirm proper tension during installation.
Neglecting to Grease the Freehub Body
While Shimano doesn’t recommend greasing the splines heavily, applying a thin coat of anti-seize or light grease is essential to prevent cassette ‘creaking’ and corrosion between the CS-6700 and the freehub. Without it, the cassette can become seized to the freehub, especially in wet climates. This oversight often leads to significant effort and potential component damage during future removal.
Also, inserting the cassette onto a dry or dirty freehub surface can accelerate spline wear and result in slight misalignment, affecting shifting under load.
Incorrect Spacer Usage
The CS-6700 cassette is available in multiple sprocket ranges, such as 11-25T and 12-30T. Depending on the cassette body and model, a spacer may be required for installation, particularly on 11-speed freehub bodies using 10-speed cassettes. Forgetting the necessary spacer causes poor gear spacing and leads to chain skipping, especially in high-torque scenarios like hill climbs.
Each variation of the CS-6700 has specific instructions for spacer placement. Failing to follow them precisely causes the derailleur to struggle with indexing, often mistaken as a derailleur tuning issue.
Failure to Monitor Cassette Wear
A worn CS-6700 cassette is harder to detect than a stretched chain, but it can be equally damaging. Riders who install a new chain on a worn cassette often experience chain slippage under load—particularly in the most used cogs.
To avoid this, replace your CS-6700 cassette after every two chains, or roughly every 4,000–6,000 miles depending on usage conditions. Ignoring this replacement window forces the drivetrain to operate inefficiently, increasing wear across the chainrings and rear derailleur jockey wheels.
Chain and Cassette Mismatch
Installing a narrow-width chain from a different groupset or generation—such as an 11-speed chain with a 10-speed CS-6700 cassette—can compromise shifting accuracy. Though some cross-compatibility exists, subtle differences in cog spacing and chain dimensions lead to incomplete engagement or noisy transitions between gears.
To ensure optimal function, use a Shimano 10-speed chain specifically designed for road drivetrains. Mismatched components place stress on drivetrain parts and reduce the life of both chain and cassette.
Overcleaning or Improper Lubrication
While a clean drivetrain runs smoother and lasts longer, overzealous cleaning—especially with degreasers—can strip vital lubricant from between cassette cogs and spacers. This leads to increased friction and accelerated wear. Pressure washing, in particular, can force moisture into places it doesn’t belong.
Use drivetrain-specific cleaning agents and avoid harsh solvents. After cleaning, apply chain lubricant carefully and allow any residue to dry before reinstalling the rear wheel.
Misaligned Derailleur Hanger Impacting Cassette Performance
A bent derailleur hanger doesn’t just affect derailleur alignment—it also leads to poor indexing across the cassette. With the CS-6700, where cog spacing is tight and shifting performance is sensitive, a hanger that’s out of true can result in chain overshoot or under-shifting.
Always check derailleur hanger alignment when installing or adjusting a cassette. Even small deviations from true alignment introduce inconsistent shifting and place uneven stress on the cassette’s teeth.
Using the Cassette with an Improper Chainline or Chainring Setup
The CS-6700 is designed for Shimano’s 10-speed road systems. Using it alongside incompatible chainrings or cranks designed for a different chainline (e.g., MTB cranks or newer 11-speed cranks) alters the effective chain angle, increasing noise and reducing efficiency.
This misalignment can also cause the chain to ride high on the cassette teeth or fail to engage fully, particularly in cross-chain positions. Always confirm chainline specifications when building or modifying your drivetrain setup.
Letting Dirt and Road Debris Build Up Between Sprockets
Because of the close spacing on the CS-6700 cassette, buildup of road grime or old lubricant between the sprockets leads to sluggish shifting. In high-dust or wet conditions, these contaminants quickly bind together, forming sticky residues that reduce gear transition speed.
Regular cleaning, using a cassette brush or dental pick between sprockets, preserves crisp shifting and reduces long-term wear.
FAQs: Avoiding CS-6700 Cassette Mistakes
Q1: How do I know if I’ve installed the CS-6700 correctly?
A1: Confirm proper spacer use, lockring torque (40 Nm), and no lateral play once installed. Shifting should be quiet and precise.
Q2: Is it okay to reuse a spacer from a different cassette model?
A2: No. Use only the original or manufacturer-recommended spacer thickness for the CS-6700 to maintain correct gear spacing.
Q3: Can I use the CS-6700 with an 11-speed freehub?
A3: Yes, but only if you add a 1.85 mm spacer behind the cassette to compensate for the wider 11-speed body.
Q4: Why is my new chain skipping on the old CS-6700 cassette?
A4: Likely due to worn cassette teeth. Replace the cassette when installing a new chain to maintain engagement under load.
Q5: Should I lubricate between cassette sprockets?
A5: No, but keep the area clean. Lubrication should be focused on the chain, not between sprockets.
Q6: How often should I inspect the CS-6700 cassette?
A6: Check every 1,000 miles for wear or damage, especially if riding in wet or dusty environments.
Conclusion
The Shimano CS-6700 cassette delivers precise, race-ready performance—but only when installed and maintained correctly. Small errors, like missing spacers or ignoring wear signs, can escalate into expensive drivetrain damage. By avoiding these costly mistakes and following best practices, you’ll extend the life of your cassette and enjoy smoother, more reliable shifting on every ride.