How to Measure Chain Wear
Aside from tires, your bike’s chain is the component that should most frequently be replaced. Wait too long, and your worn out chain will reduce shifting quality and shorten your drivetrain’s lifespan. That’s a scenario best avoided considering that a Dura Ace cassette and chainring cost upwards of $500 combined.
But how often should you replace your chain? Before answering that question, it helps to understand a little about the process of chain wear. As your chain ages, each link’s internal bushings slowly lengthen. In turn, your now-longer chain puts added pressure on your cassette cog and chainring teeth, causing them to wear faster and reducing shifting quality.
To avoid accelerated wear, replace your road bike’s chain every 1,500-2,000 miles, and your mountain bike’s chain every 5-6 months. Just remember that these are only general guidelines, and that no two chains will wear at exactly the same rate because no two riders are exactly the same.
If you meticulously clean and lightly lubricate your chain, never ride on wet roads, weigh a spindly 135 pounds, and always spin low gears, your chain will last longer. However, if you’re a Clydesdale-sized rider that pushes big gears, rides in the rain, and never cleans or lubes your chain, it will wear out much faster.
These differences necessitate more precise chain wear measuring tools such as the Park CC-3 gauge or Performance’s own Spin Doctor version. To use either tool, apply pressure to a pedal so the top of the chain is taut, then drop the measuring tool in place and read the results. Indicators on the tool will tell you whether or not it’s time to replace your chain.
You can also measure chain wear using a 12-inch ruler. To do this, first remember that all modern chains have rivets every half inch, and that you will be measuring from one rivet to another one that is 12 inches away.
First draw the top of the chain taut, and align the end of the ruler at the zero-inch mark with the center of a rivet. Note where the ruler’s 12-inch mark aligns. If it’s dead center on a rivet, the chain is in like-new condition. If the rivet is less than a 1/16 of an inch ahead of the 12-inch mark, then the chain is showing some wear but is still serviceable. And if the rivet is more than 1/16 of an inch ahead of the 12-inch mark, it’s time to replace the chain.Bike Parts and Components