Chains do not stretch. The holes that contain the pins elongate over time and the cumulative effect makes the chain longer.

Using a worn chain will wear out other components – cassette cogs, dérailleur, and the chainring – as they have fixed spacing which does not mesh as well with the longer stretched chain.

Some of the side effects of using a worn chain on your bike can be worn chain rings causing chain suck and the gears not shifting as well. In really bad cases there might actually be some physical damage.

Replacing a chain is much cheaper than replacing a chainring set, cassette or dérailleur. These components should last up to 6 chain replacements according to some Industry experts, provided the chains are maintained well.

The durability of a chain is affected by riding style, weather conditions, lubrication and the quality of the component themselves.
Hence it’s difficult to change a chain on the basis of distance or time. The best way to check for chain wear is to check the length of the chain to figure out if the chain has actually stretched.

snap of chain pitch, by Jonathan Levy

Steps to check for chain stretch

  • The distance between two pins on the chain (called the pitch of the link) should be half an inch (every chain follows this).
  • A link pair (two adjoining chain links) should measure an inch
  • 12 link pairs on a new unstretched chain measure 12 inches (304.8mm).
  • To allow for manufacturing inaccuracies we leave a 0.5% tolerance so that gives us a + or – 1.5mm over 12 link pairs.

The easiest way to figure out chain stretch is to check the length of 12 link pairs on your bike, which should ideally measure anywhere between 303.3mm and 305.3mm

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About the Author

Rohan Kini

WHAT I LOVE ABOUT CYCLING I love riding my bike. Whether it's a simple commute, a high-intensity road race, a jaw-grinding brevet, fixie rides thru packed Indian city or a kick-ass technical single track – I love it all. Apart from riding bicycles, I love being all geeky and know everything there is to know about bicycles, technology, bike fit, and service. I started BUMSONTHESADDLE to share this passion for cycling. DISCIPLINE: Partial towards MOUNTAIN BIKING but love it all CURRENT BIKE(S): Specialized Rockhopper, Specialized Tarmac, Pure Cycles Original DREAM BIKE: S-Works Epic HT & S-Work Roubaix OTHER PASSIONS: Technology, Photography, Baking, Travel, and Reading

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