The chain is the centre of the drivetrain and the component under greatest stress.
The simplest way to check its condition is by using the aptly-named ‘chain checker’ tool, which measures the distance between links to gauge wear. Investing in this cheap and easy to use device is a course of action we’d recommend, but if you don’t have one to hand and are concerned that your worn chain is damaging other, more expensive components in your drivetrain – the chainrings, and cassette – there are some easy methods of checking wear.
Andy’s tips include pulling the ‘top’ section of the chain – the series of links above the chainstay – towards you to gauge the amount of side deflection. The bushings in the chain are subject to tremendous torque, he says, and compares a worn chain to a plastic, toy snake, where the head moves independently of the tail. “You can easily see the side slop in a chain,” he adds.
Another method is to lift the chain from the chainring. If you’re able to see daylight beneath three or four links, it’s time to replace the chain. A final method involves holding the rear wheel with one hand and placing pressure on the driveside pedal with the other. Paying close attention the links on the ‘top’ of the chainring will reveal if the chain is worn: one that is ready for replacement will ‘ride up’ on the teeth of the chainring, rather than sitting flush upon them.