There aren’t many components more important on a bike than its chain. However, it’s easy to overlook chain wear that can cause serious inefficiency in the drivetrain and even risk a chain failure.
Meshing with the teeth of both your chainrings and sprockets, the chain transfers the energy produced by your legs to the rear wheel. As it does so both its rollers and pins will slowly wear out. Often referred to as having stretched, the chain’s length will actually remain the same, but its ability to do its job will get less and less until eventually you’ll find your gears slipping.
Hugely affected by the conditions you ride in, and the amount of cleaning you can be bothered with, its lifespan can be hard to predict. Luckily there are ways to diagnose exactly the state yours is in.
Let your chain get too worn and your shifting will suffer, along with the state of your chainrings, cassette and jockey wheels. However, change it before its too degraded and you’ll prolong the life of the other bits of your drivetrain. Most manufacturers recommend you replace your chain once the gap between the rollers has grown (due to wear) by 0.75%.
Follow our guide to see whether your chain is still in fighting shape.
Related questions you can explore with Ask Cyclist, our new AI search engine.
How to check your bike’s chain for wear
1. Check your chain with a chain checker
Various tools exist to measure chain wear; from variable gauges to digital calipers and simple drop-in models. All do the same job in measuring the wear on the rollers between a short section of chain.
Easy to use, you simply slot them in between a set number of links. Drop-in models will fit on one side. Should the second end also drop in, this will usually indicate either 0.75% or 1% wear; it’ll be marked on the tool. More complex gauges may require you to expand them to give a more accurate reading.
2. Check for wear without tools
Pop your chain onto the largest chainring. Find the point in the middle of the section of chain that's engaged with the chainring's teeth. This will be around the 3 o'clock position. Try to pull the chain away from the chainring.
A new chain detaching only slightly from the chainring
If you can see more than a sliver of daylight, it's a good indication your chain is knackered. See the images above and below for comparison.
A worn chain pulling away easily from the chainring
This is only a rough and ready guide, though, so if you notice a significant gap developing, now would be a good time to get a bike shop to check it for you more accurately, or indeed to invest in a tool to do it yourself. It's a ten second job that can save you a fortune. The tool will have paid for itself in no time at all.
- If you find your chain is worn, check out our bike chain buyer's guide
Need more tips and tricks for bike maintenance? Head over to our Tutorials hub for more alongside a stack of training advice.
