Chain wear, categorised as chain stretch, becomes a concern with intensive 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 in fact the bushing is part of the inner plate) rather than elongation of the sideplates.[8] The tension developed by pedaling is insufficient to trigger the latter. Because the spacing from link to link on a put on chain is longer than the 1⁄2 inch (12.7 mm) specification, those links will not precisely fit the areas between teeth on the sprockets, resulting in increased wear upon the sprockets and possibly chain skip on derailleur drive trains, where pedaling tension causes the chain to slide up more than the tops of the sprocket teeth and skip to another alignment, that reduces power transfer and makes pedaling uncomfortable.
Since chain wear is strongly frustrated by dirt engaging in the links, the duration of a chain depends mostly about how well it is cleaned (and lubricated) and will not depend on the mechanical load.[6] Therefore, well-groomed chains of heavily used racing bicycles will most likely last longer when compared to a chain on a lightly used city bike that’s cleaned less. Based on make use of and cleaning, a chain can last only 1 1,000 kilometres (600 miles) (electronic.g. in cross-country use, or all-weather use), 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 perfectly groomed high-quality chains, single-gear, or hub-gear chains (ideally with a full cover chain guard).[9][10]
Nickel-plated chain also confers a measure of self-lubrication to its shifting parts as nickel is certainly a relatively non-galling steel.[dubious – discuss]
Chain wear rates are highly variable, so alternative by calendar is probable premature or continued usage of a worn chain, damaging to back sprockets. One Drive Chain method to measure wear has been a ruler or machinist’s guideline.[11] Another is with a chain wear tool, which typically includes a “tooth” around the same size found on a sprocket. They are simply positioned on a chain under light load and survey a “go/no-proceed” result-if the tooth drops in every just how, 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 actions 10 1⁄16 in . (256 mm) (0.7% wear).[5] A safer period to replace a chain is when 24 half-links in the outdated chain measure 12 1⁄16 inches (306 mm) (0.5% wear). If the chain offers put on beyond this limit, the trunk sprockets are also likely to wear, in extreme cases followed by the front chainrings. In this case, the ‘skipping’ mentioned above is liable to continue even following the chain is replaced, as one’s teeth of the sprockets could have become unevenly put on (in extreme cases, hook-shaped). Replacing worn sprocket cassettes and chainrings after missing the chain replacement window is a lot more expensive than replacing a put on chain.