Chain wear, often called chain stretch, becomes an issue with extensive cycling. The put on is removal of materials from the bushings and pins (or half-bushings, in the Sedis style, also, called “bushing-less”, where the bushing is section of the internal plate) instead of elongation of the sideplates.[8] The tension produced by pedaling is insufficient to trigger the latter. Because the spacing from link to hyperlink on a worn chain is longer compared to the 1⁄2 inch (12.7 mm) specification, those links will not precisely fit the spaces between teeth on the sprockets, leading to increased wear upon the sprockets and perhaps chain skip upon derailleur drive trains, where pedaling tension causes the chain to slide up more than the tops of the sprocket teeth and skip to the next alignment, that reduces power transfer and makes pedaling uncomfortable.

Since chain wear is strongly aggravated by dirt getting into the links, the lifetime of a chain depends mostly about how well it really is cleaned (and lubricated) and will not depend on the mechanical load.[6] Therefore, well-groomed chains of heavily used racing bicycles will often last longer than a chain on a lightly used city bike that is cleaned less. Depending on use and cleaning, a chain can last only 1 1,000 kilometres (600 miles) (e.g. in cross-country use, or all-weather make use of), 3,000 to 5,000 km (2,000 to 3,000 mi) for well-maintained derailleur chains, or even more than 6,000 kilometres (4,000 mi) for properly groomed high-quality chains, single-gear, or hub-gear chains (preferably with a complete cover chain guard).[9][10]

Nickel-plated chain also confers a measure of self-lubrication to its shifting parts as nickel is a relatively non-galling metallic.[dubious – discuss]

Chain wear prices are highly variable, so substitute by calendar is likely premature or continued use of a worn chain, damaging to rear sprockets. One way to measure wear has been a ruler or machinist’s rule.[11] Another is with a chain wear device, which typically has a “tooth” around the same size found on a sprocket. They are simply placed on a chain under light load and statement a “go/no-move” result-if the tooth drops in all the way, the chain ought to be replaced.

Twenty half-links in a fresh chain measure 10 inches (254 mm), and alternative is recommended prior to the old chain procedures 10 1⁄16 in . (256 mm) (0.7% wear).[5] A safer time to replace a chain is when 24 half-links in the aged chain measure 12 1⁄16 inches (306 mm) (0.5% wear). If the chain has worn beyond this limit, the rear sprockets are also likely to put on, in Drive Chain extreme cases followed by the front chainrings. In this instance, the ‘skipping’ mentioned above is liable to continue even after the chain is changed, as the teeth of the sprockets could have become unevenly put on (in extreme cases, hook-shaped). Replacing worn sprocket cassettes and chainrings after lacking the chain replacement window is much more expensive than simply replacing a put on chain.