What chain size and length do I need?

December 24, 2020 14:53

All current Brompton bicycles are built with 3/32” width chains.

The chain must have the correct number of links and this will depend on the combination of chainring and sprocket/s as set out below.

Chainwheel		ONE rear sprocket			TWO rear sprockets
54T	12T or 13T		100L	16T/12T, 16T/13T or 15T/13T		102L
50T	12T or 13T		98L	16T/12T, 16T/13T or 15T/13T		100L


44T	12T, 13T, 14T		96L	16T/12T, 16T/13T or 15T/13T		98L

Generally, all 2 speed bikes are fitted with a 54T chainwheel, 6 and 3 speed bikes are fitted with a 50T chainwheel and B75 bikes are fitted with a 44T. You can check this on the chainwheel itself which has a number printed on it.

Chains for each of the different gearing options are available as spare parts from authorised dealers. The 3/32” width chains come with a tool-free connecting link. As with our other spares and accessories, these are not sold directly from our factory but are available from authorised Brompton dealers either directly from their stock, or by asking them to order the parts.

When fitting a new chain the sprockets must be replaced at the same time.

Some earlier Bromptons will have been built with 1/8” chains and sprockets. The combinations of chain wheel and sprocket required are the same as in the table above, but the 1/8” chain must, of course, be used in combination with 1/8” sprockets only. The tool-free connecting link cannot be used with a 1/8” width chain.

Some spares can be ordered online in some countries or through an authorised Brompton retailer.

Click on dealer locator to find your nearest one.

De quelle taille et quelle longueur de chaîne ai-je besoin ?