Roller Chain Identification (ANSI B29.1)

ANSI roller chain is identified by a numbering system where the first digit(s) indicate the pitch in 1/8-inch increments.

ANSI SizePitchRoller DiaInner Width
#250.250"0.130"0.125"
#350.375"0.200"0.188"
#400.500"0.312"0.312"
#500.625"0.400"0.375"
#600.750"0.469"0.500"
#801.000"0.625"0.625"