To alleviate poor shifting and uneven drivetrain wear, manufacturers recommend chain replacement before rear cog replacement. Now you can quickly and accurately determine the wear and stretch of any chain with Park Tool Chain Checker. Simply insert the Chain Checker’s pins into two links, lightly press the swing arm gauge, and then check the gauge window for an accurate reading.
The CC-2 is compatible with all rear derailleur chains.
– For 9 and 10-speed chains, replace chain at or just before the 0.75% reading
– For 11 and 12-speed chains, replace at or just before the 0.5% reading
Check with manufacturer for specific replacement instructions.