Park Tool CC-4 Chain Wear Indicator

While a ruler can measure chain stretch, it is often imprecise because it doesn't account for roller wear or the specific tension required for an accurate reading. The CC-4 is designed to isolate the wear on the rollers and pins, giving you a definitive measurement that tells you exactly when your chain is worn enough to damage your cassette and chainrings.

Yes, the CC-4 is fully compatible with all 5 to 12-speed derailleur chains, including SRAM AXS and other modern high-speed drivetrains. Its laser-cut design is specifically engineered to accommodate the tighter tolerances of these newer chains.

These percentages represent the amount of 'stretch' or wear in your chain. A reading of 0.5% is generally the replacement threshold for most modern 11 and 12-speed chains, while 0.75% is the standard replacement point for older 5 to 10-speed chains.

Not at all. The CC-4 uses a simple drop-in design that contacts the chain in three places, making it nearly foolproof. You simply insert the tool into the chain links, and if it drops all the way in, you know it's time to replace your chain.

It is good practice to check your chain every few hundred miles, or more frequently if you ride in wet, muddy, or gritty conditions. Catching wear early is the single most effective way to extend the life of your more expensive drivetrain components like your cassette and chainrings.