Roller chains built to the American ANSI standard conform to the ISO 606, ANSI B29.1 and DIN 8188 standards. The most important dimension of a roller chain is its pitch. The pitch of a roller chain is usually measured in fractions of an inch. When using the American standard, the pitch of the chain is usually measured in eights of an inch in accordance with the ANSI standard. The first digit of the ANSI number indicates the chain’s pitch in eights of an inch, the second indicates the type of chain (0 = roller chain) and the last digit indicates the number of rows. For example, ANSI 40-2: The 4 indicates the chain has a pitch of 4/8”, the 0 indicates it is a roller chain, and the 2 indicates it is a two-row chain, more commonly known as a duplex chain. ANSI chains may also be referenced using the European system, in which case an ANSI 80-1 chain would be reported as 16A-1.

British standard roller chains use a larger-diameter pin than American standard roller chains. Because of this, British standard chains have slightly better wear resistance. ANSI chains are also available in heavy versions with thicker side plates. Heavy roller chains with thicker side plates offer higher impact strength than normal chains, making them perfect for high-stress applications. Double capacity options are also available.

ANSI standard roller chains are commonly used in places such as agricultural machinery, conveyors for unloading peat or woodchips from trucks and a number of other applications. For a table of ANSI chain dimensions, see the link below.