When and How Often Should You Replace the Chain?
Even with the best care and lubrication, the chain on the bike eventually wears out – especially when you’re mountain biking, where excess dirt and moisture are a given. When the chain wears out, this is referred to as "stretch": friction between the individual parts of the chain creates and increases play in the links over time, which stretches the chain as a whole. Replacing the chain in a timely manner protects the environment as well as your bank account: if you keep an eye on the wear and replace the chain at the right time, you can use your chainring and cassette for longer. After reaching a certain amount of stretch, the worn chain wears down the cassette and chainring so much that a new chain would no longer work on them. This leads to the other (more expensive) components needing to be replaced. Often, when you ask how often the chain should be swapped out, you’re usually given an estimate in kilometres. However, there are too many external influences that have an impact on the wear of the chain, so this number is not always firm. A chain wear indicator will be much more useful for seizing on the right moment. You can use it to check the condition of your chain quickly and easily at any time. Repeatedly replacing the chain doesn't work forever, though. The cassette should also be eventually replaced – you can learn more about when and how to replace it in the article linked below. Replacing the chain is also necessary if your chain has been damaged off-road, for example by hard impacts with rocks. Twisted or bent chain links could eventually become a safety hazard. If you are building a new bike, you can start at step two to fit the new chain.