Brompton's 10-speed chain (made by YBN) for every 4-speed and 12-speed Brompton: P Line, T Line, C Line and all their Electric versions. Not for 2, 3 or 6-speed bikes, which take the 3/32" chain. Pick the length for your chainring: 102 links for a 50T geared bike or a 54T/56T single-speed, 104 links for 54T geared. A 56T geared bike needs the 106-link chain. Need 98 or 100 links (50T single-speed, or 44T geared)? Order the 102 and tell us — we shorten it free before it ships. Not sure which one you need? See our guide: Which chain does my Brompton need? Fresh Drivetrain for Brompton Advance 4- and 12-Speed Systems The Brompton Advance Chain is the correct replacement chain for bikes using the Advance 4-speed external gearing, including 4- and 12-speed P Line, T Line, and newer C Line Electric models. Its narrow profile is tuned to work with the compact cassette and Advance derailleur so shifts stay smooth, quiet, and predictable. Chains wear over time, stretching and accelerating wear on cogs and chainrings. Replacing yours with the proper Advance-spec chain restores crisp shifting and helps protect the rest of your drivetrain. Each chain comes ready to size and join with a dedicated connecting link for straightforward workshop or at-home installs. Simple. Solid. Reliable. Designed specifically for Brompton Advance drivetrains on 4- and 12-speed bikes (P Line, T Line, and C Line Electric with Advance gears). Narrow multi-speed profile matched to the Advance cassette and derailleur for accurate, consistent indexing. Supplied with a connecting link for easy fitting, removal, and cleaning with master-link pliers. Available in different link lengths to suit various chainring and sprocket combinations; match to your original chain or Brompton’s chain length guide. Best practice is to replace rear sprockets when fitting a new chain to reduce skipping and extend drivetrain life. Not compatible with earlier 1-, 2-, 3-, or 6-speed Brompton drivetrains (A Line, C Line, or pre-Advance Brompton Electric).
