Brompton bottom bracket cartridge JIS119mm

Brompton bottom bracket cartridge- JIS 119mm

Comes complete with two crank bolts.

Essential if you are changing from a 'fixed' to 'spider' crankset

This Bottom Bracket is compatible in size with all Brompton bikes (they have a 68mm bottom bracket shell), but if you are replacing and have the fixed (non-spider) crankset, then you will also have to replace the crankset

Please note - if you are replacing the older bottom bracket, you also need to replace the front chain ring and left hand crank.

A bit of Brompton Bottom Bracket Alliteration History

Brompton bicycles use what is known as a square taper bottom bracket ... but its not quite that simple

In January 2013 Brompton introduced a new crankset, known as the spider crankset. This had a detachable chainring, making it easier to replace just part due to wear or change gearing

This new chainset uses a different bottom bracket to the older fixed chainset - this is known as JIS (Japanese International Standard) as opposed to ISO (International Standards Organisation). These look almost identical - but the JIS has a slight notch cut out of the end

During 2015 the Brompton JIS bottom bracket was changed from FAG (the manufacturer) to StrongLight (the documentation in the packet hasn't yet changed with it)

During 2017 the old ISO  bottom bracket (not this one, but the one used with the old fixed crankset) was discontinued

Also during 2017 the Stronglight bottom bracket was replaced (as an after-market option) by the Thun IBEX bottom bracket. When Brompton recalled the FAG bottom brackets (different one were being used on factory bikes to after-market sales), the replacements were also these Thun IBEX bottom brackets

In September 2017 Brompton announced a recall of the FAG JIS bottom brackets - these were factory installed  (between April 2014 and May 2017) bottom brackets, not the ones sold on the after market

Bottom bracket removal and installation

Before removing the bottom bracket from your Brompton, you will also need to remove the crank arms (this whole process will be easier if you have a workstand)

We made the video below to show how to remove the old bottom bracket

Once the cranks are removed, you can remove the bottom bracket itself

This other great article from Park Tool shows how to remove and install the bottom bracket

Brompton 2021 Q part code: Q100001
Brompton Q part code: QBBCART-119-JIS
Brompton part number: 9044016