Brompton Chain 3 32nd inch 96 link - QCHAIN096DR

The chainring is the big ring by the pedals; the size is usually stamped on it (44T, 50T or 54T). If it isn't, put a piece of tape on one tooth and count around. The rear sprocket is on the back wheel: count the teeth on the largest one. Most 3-speeds have a 13T, and most 2- and 6-speeds have a 16T as their largest. Those two numbers pick the chain length in the Brompton chain guide.

Yes for every 1-, 2-, 3- and 6-speed A Line and C Line, including older bikes that originally came with a wider 1/8-inch chain: this 3/32-inch, 8-speed chain fits them all. It is not for 4-speed or 12-speed bikes (P Line, T Line and the 2026-on C Line), which need the narrower SL Advance chain.

No. The chain comes with a SRAM PowerLink, so it joins and comes apart by hand. Wrap it over the chainring and sprocket, bring the two ends together, snap the PowerLink in and pull the chain taut to lock it. A pair of master-link pliers makes opening it easier later, but isn't required.

Almost always. Chain and sprockets wear together, and a new chain on a worn sprocket tends to skip under load. Brompton recommends fitting a new sprocket (or 2- and 6-speed sprocket pair) with every new chain, and so do we. Chainrings last several chains and only need replacing when the teeth look hooked.