{
  "name": "ANSI roller chain sizes and their ISO 606 A-series and BS/DIN B-series counterparts",
  "description": "Industrial roller chain is sold under two numbering systems that look interchangeable and are not. The American system numbers chains 40, 50, 60 and so on, in eighths of an inch of pitch. The British/European system numbers them 08B, 10B, 12B. ISO 606 covers both: its A series is the American chain under a metric name (ANSI 40 is ISO 08A -- the same chain), and its B series is the British chain, which shares the pitch but is a different chain, with a different roller diameter and a different inner width, needing its own sprockets. Somebody replacing chain or matching a sprocket across the two systems has to know which of those two relationships they are looking at, and no catalog states it in one place: manufacturers print an ANSI dimensional table and a separate BS/DIN dimensional table in the same document, never cross-referenced, and the pitch match has to be worked out by eye. Each record here is one ANSI chain number with its pitch, roller diameter and inner width; its ISO 606 A-series name where a publisher states one; and the BS/DIN B-series chain that shares its pitch, with that chain's own pitch, roller diameter and inner width printed alongside, so the difference is visible rather than asserted. Answers 'what is the metric equivalent of ANSI 40 chain', 'is BS 08B the same as ANSI 40', 'ANSI 40 vs 08A vs 08B', 'roller chain size conversion chart'. In scope: the ANSI sizes that the source catalog prints with a roller diameter and that have a B-series chain of the same pitch. Out of scope, and why: ANSI 25 and 35, which are rollerless -- the catalog prints a bushing diameter for them, not a roller diameter, so there is no like-for-like comparison to make; ANSI 41, which has no single-line standard dimension row in the source; and ANSI 180, whose 2 1/4 inch pitch has no B-series counterpart in the source.",
  "url": "https://referencesource.org/ansi-to-iso-roller-chain-cross-reference/",
  "licence": "Manufacturer catalog data; cite source, do not reproduce the whole table -- take the individual dimension facts and the attributed quote, not the document",
  "last_verified": "2026-09-16",
  "stale_after": "2028-08-31",
  "sources": [
    "https://www.ustsubaki.com/wp-content/uploads/tsubaki-roller-chain-catalog-compressed.pdf",
    "https://www.ametric.com/images/document/chains-roller.pdf"
  ],
  "records": [
    {
      "ansi_chain_number": "40",
      "ansi_pitch": "0.500",
      "ansi_roller_diameter": "0.312",
      "ansi_width_between_roller_link_plates": "0.312",
      "iso_a_series_number": "08A",
      "bs_din_chain_number": "08B",
      "bs_din_pitch": "0.500",
      "bs_din_roller_diameter": "0.335",
      "bs_din_width_between_roller_link_plates": "0.305",
      "id": "40",
      "url": "https://referencesource.org/ansi-to-iso-roller-chain-cross-reference/40/",
      "source": "https://www.ustsubaki.com/wp-content/uploads/tsubaki-roller-chain-catalog-compressed.pdf",
      "source_quote": "P Roll dia. W T H h D 40 0.500 0.312 0.312 0.060 0.472 0.409 0.156",
      "verified_fields": [
        "ansi_pitch",
        "ansi_roller_diameter",
        "ansi_width_between_roller_link_plates",
        "bs_din_pitch",
        "bs_din_roller_diameter",
        "bs_din_width_between_roller_link_plates",
        "iso_a_series_number"
      ],
      "derived_fields": [
        "ansi_chain_number",
        "bs_din_chain_number"
      ]
    },
    {
      "ansi_chain_number": "50",
      "ansi_pitch": "0.625",
      "ansi_roller_diameter": "0.400",
      "ansi_width_between_roller_link_plates": "0.375",
      "iso_a_series_number": "10A",
      "bs_din_chain_number": "10B",
      "bs_din_pitch": "0.625",
      "bs_din_roller_diameter": "0.400",
      "bs_din_width_between_roller_link_plates": "0.380",
      "id": "50",
      "url": "https://referencesource.org/ansi-to-iso-roller-chain-cross-reference/50/",
      "source": "https://www.ustsubaki.com/wp-content/uploads/tsubaki-roller-chain-catalog-compressed.pdf",
      "source_quote": "P Roll dia. W T H h D 50 0.625 0.400 0.375 0.080 0.591 0.512 0.200",
      "verified_fields": [
        "ansi_pitch",
        "ansi_roller_diameter",
        "ansi_width_between_roller_link_plates",
        "bs_din_pitch",
        "bs_din_roller_diameter",
        "bs_din_width_between_roller_link_plates",
        "iso_a_series_number"
      ],
      "derived_fields": [
        "ansi_chain_number",
        "bs_din_chain_number"
      ]
    },
    {
      "ansi_chain_number": "60",
      "ansi_pitch": "0.750",
      "ansi_roller_diameter": "0.469",
      "ansi_width_between_roller_link_plates": "0.500",
      "iso_a_series_number": "12A",
      "bs_din_chain_number": "12B",
      "bs_din_pitch": "0.750",
      "bs_din_roller_diameter": "0.475",
      "bs_din_width_between_roller_link_plates": "0.460",
      "id": "60",
      "url": "https://referencesource.org/ansi-to-iso-roller-chain-cross-reference/60/",
      "source": "https://www.ustsubaki.com/wp-content/uploads/tsubaki-roller-chain-catalog-compressed.pdf",
      "source_quote": "P R W T H h D 60 0.750 0.469 0.500 0.094 0.713 0.614 0.234",
      "verified_fields": [
        "ansi_pitch",
        "ansi_roller_diameter",
        "ansi_width_between_roller_link_plates",
        "bs_din_pitch",
        "bs_din_roller_diameter",
        "bs_din_width_between_roller_link_plates",
        "iso_a_series_number"
      ],
      "derived_fields": [
        "ansi_chain_number",
        "bs_din_chain_number"
      ]
    },
    {
      "ansi_chain_number": "80",
      "ansi_pitch": "1.000",
      "ansi_roller_diameter": "0.625",
      "ansi_width_between_roller_link_plates": "0.625",
      "iso_a_series_number": "16A",
      "bs_din_chain_number": "16B",
      "bs_din_pitch": "1.000",
      "bs_din_roller_diameter": "0.625",
      "bs_din_width_between_roller_link_plates": "0.670",
      "id": "80",
      "url": "https://referencesource.org/ansi-to-iso-roller-chain-cross-reference/80/",
      "source": "https://www.ustsubaki.com/wp-content/uploads/tsubaki-roller-chain-catalog-compressed.pdf",
      "source_quote": "P Roll dia. W T H h D 80 1.000 0.625 0.625 0.125 0.949 0.819 0.312",
      "verified_fields": [
        "ansi_pitch",
        "ansi_roller_diameter",
        "ansi_width_between_roller_link_plates",
        "bs_din_pitch",
        "bs_din_roller_diameter",
        "bs_din_width_between_roller_link_plates",
        "iso_a_series_number"
      ],
      "derived_fields": [
        "ansi_chain_number",
        "bs_din_chain_number"
      ]
    },
    {
      "ansi_chain_number": "100",
      "ansi_pitch": "1.250",
      "ansi_roller_diameter": "0.750",
      "ansi_width_between_roller_link_plates": "0.750",
      "iso_a_series_number": "20A",
      "bs_din_chain_number": "20B",
      "bs_din_pitch": "1.250",
      "bs_din_roller_diameter": "0.750",
      "bs_din_width_between_roller_link_plates": "0.770",
      "id": "100",
      "url": "https://referencesource.org/ansi-to-iso-roller-chain-cross-reference/100/",
      "source": "https://www.ustsubaki.com/wp-content/uploads/tsubaki-roller-chain-catalog-compressed.pdf",
      "source_quote": "P R W T H h D 100 1.250 0.750 0.750 0.156 1.185 1.024 0.375",
      "verified_fields": [
        "ansi_pitch",
        "ansi_roller_diameter",
        "ansi_width_between_roller_link_plates",
        "bs_din_pitch",
        "bs_din_roller_diameter",
        "bs_din_width_between_roller_link_plates",
        "iso_a_series_number"
      ],
      "derived_fields": [
        "ansi_chain_number",
        "bs_din_chain_number"
      ]
    },
    {
      "ansi_chain_number": "120",
      "ansi_pitch": "1.500",
      "ansi_roller_diameter": "0.875",
      "ansi_width_between_roller_link_plates": "1.000",
      "iso_a_series_number": "24A",
      "bs_din_chain_number": "24B",
      "bs_din_pitch": "1.500",
      "bs_din_roller_diameter": "1.000",
      "bs_din_width_between_roller_link_plates": "1.000",
      "id": "120",
      "url": "https://referencesource.org/ansi-to-iso-roller-chain-cross-reference/120/",
      "source": "https://www.ustsubaki.com/wp-content/uploads/tsubaki-roller-chain-catalog-compressed.pdf",
      "source_quote": "P R W T H h D 120 1.500 0.875 1.000 0.187 1.425 1.228 0.437",
      "verified_fields": [
        "ansi_pitch",
        "ansi_roller_diameter",
        "ansi_width_between_roller_link_plates",
        "bs_din_pitch",
        "bs_din_roller_diameter",
        "bs_din_width_between_roller_link_plates",
        "iso_a_series_number"
      ],
      "derived_fields": [
        "ansi_chain_number",
        "bs_din_chain_number"
      ]
    },
    {
      "ansi_chain_number": "140",
      "ansi_pitch": "1.750",
      "ansi_roller_diameter": "1.000",
      "ansi_width_between_roller_link_plates": "1.000",
      "bs_din_chain_number": "28B",
      "bs_din_pitch": "1.750",
      "bs_din_roller_diameter": "1.100",
      "bs_din_width_between_roller_link_plates": "1.220",
      "id": "140",
      "url": "https://referencesource.org/ansi-to-iso-roller-chain-cross-reference/140/",
      "source": "https://www.ustsubaki.com/wp-content/uploads/tsubaki-roller-chain-catalog-compressed.pdf",
      "source_quote": "P R W T H h D 140 1.750 1.000 1.000 0.219 1.661 1.433 0.500",
      "verified_fields": [
        "ansi_pitch",
        "ansi_roller_diameter",
        "ansi_width_between_roller_link_plates",
        "bs_din_pitch",
        "bs_din_roller_diameter",
        "bs_din_width_between_roller_link_plates"
      ],
      "derived_fields": [
        "ansi_chain_number",
        "bs_din_chain_number"
      ]
    },
    {
      "ansi_chain_number": "160",
      "ansi_pitch": "2.000",
      "ansi_roller_diameter": "1.125",
      "ansi_width_between_roller_link_plates": "1.250",
      "bs_din_chain_number": "32B",
      "bs_din_pitch": "2.000",
      "bs_din_roller_diameter": "1.150",
      "bs_din_width_between_roller_link_plates": "1.220",
      "id": "160",
      "url": "https://referencesource.org/ansi-to-iso-roller-chain-cross-reference/160/",
      "source": "https://www.ustsubaki.com/wp-content/uploads/tsubaki-roller-chain-catalog-compressed.pdf",
      "source_quote": "P R W T H h D 160 2.000 1.125 1.250 0.250 1.898 1.638 0.562",
      "verified_fields": [
        "ansi_pitch",
        "ansi_roller_diameter",
        "ansi_width_between_roller_link_plates",
        "bs_din_pitch",
        "bs_din_roller_diameter",
        "bs_din_width_between_roller_link_plates"
      ],
      "derived_fields": [
        "ansi_chain_number",
        "bs_din_chain_number"
      ]
    },
    {
      "ansi_chain_number": "200",
      "ansi_pitch": "2.500",
      "ansi_roller_diameter": "1.562",
      "ansi_width_between_roller_link_plates": "1.500",
      "bs_din_chain_number": "40B",
      "bs_din_pitch": "2.500",
      "bs_din_roller_diameter": "1.550",
      "bs_din_width_between_roller_link_plates": "1.500",
      "id": "200",
      "url": "https://referencesource.org/ansi-to-iso-roller-chain-cross-reference/200/",
      "source": "https://www.ustsubaki.com/wp-content/uploads/tsubaki-roller-chain-catalog-compressed.pdf",
      "source_quote": "P R W T H h D 200 2.500 1.562 1.500 0.312 2.374 2.047 0.781",
      "verified_fields": [
        "ansi_pitch",
        "ansi_roller_diameter",
        "ansi_width_between_roller_link_plates",
        "bs_din_pitch",
        "bs_din_roller_diameter",
        "bs_din_width_between_roller_link_plates"
      ],
      "derived_fields": [
        "ansi_chain_number",
        "bs_din_chain_number"
      ]
    },
    {
      "ansi_chain_number": "240",
      "ansi_pitch": "3.000",
      "ansi_roller_diameter": "1.875",
      "ansi_width_between_roller_link_plates": "1.875",
      "bs_din_chain_number": "48B",
      "bs_din_pitch": "3.000",
      "bs_din_roller_diameter": "1.900",
      "bs_din_width_between_roller_link_plates": "1.800",
      "id": "240",
      "url": "https://referencesource.org/ansi-to-iso-roller-chain-cross-reference/240/",
      "source": "https://www.ustsubaki.com/wp-content/uploads/tsubaki-roller-chain-catalog-compressed.pdf",
      "source_quote": "P R W T H h D 240 3.000 1.875 1.875 0.375 2.850 2.457 0.937",
      "verified_fields": [
        "ansi_pitch",
        "ansi_roller_diameter",
        "ansi_width_between_roller_link_plates",
        "bs_din_pitch",
        "bs_din_roller_diameter",
        "bs_din_width_between_roller_link_plates"
      ],
      "derived_fields": [
        "ansi_chain_number",
        "bs_din_chain_number"
      ]
    }
  ]
}