This includes the now famous (as of September 2017) Bottom Bracket (recalled due to a defect affecting up to 0.02% of Bromptons).
Here you can find, chains and chain tensions / ...
This includes the now famous (as of September 2017) Bottom Bracket (recalled due to a defect affecting up to 0.02% of Bromptons).
Here you can find, chains and chain tensions / derailleurs, pedals, sprocket sets and crank sets / chain rings.
Subcategories
The bottom bracket is a bit of an unsung hero in the bike world - it sits inside the bike frame (screwed in) and then has the pedal cranks bolted onto it or crank arms / spindle pushed through it
(Brompton obviously recognise the importance as their code for the bottom bracket is Q100001 - i.e. part no 1 on the bike!)
Every turn of the pedal rotates the spindle inside, keeping both cranks / pedals turning together - it has bearings inside which keep it moving smoothly (until they wear out)
The traditional Brompton (or A Line / C Line / P Line) use a sealed bottom bracket (i.e. no replaceable parts inside) with a square taper crank fitting (older cranksets use a ISO fitting and newer spider cranksets use a JIS fitting)
These Bromptons use a 119mm length spindle and a 68mm shell
It is possible to change to other styles of bottom bracket
With the introduction of the T Line came a different style of bottom bracket with external replaceable bearings
This bottom bracket (made for Brompton by FSA) can be retro-fitted to any Brompton - but also needs the new superlight crankset
The Brompton chain tensioner keeps the chain taught (so that the chain doesn't fall off of the bike when folding), and acts as a derailleur on Bromptons with two rear sprockets.
Current Brompton folding bikes use two different specs of chains:
We made a short video on A / C Line chain length calculation
A: The chain length for a Brompton C line can be worked out based on the number of teeth on the front chain ring and the number of teeth on the largest rear sprocket - as shown in the table below (or watching the video even further down)
Largest Rear Sprocket | Chain required | Chainring size | Note |
12T/13T/14T | QCHAIN096DR | 44T | Reduced gearing 3 speed / single speed |
15T/16T | QCHAIN098DR | 44T | Reduced gearing 6 speed |
13T | QCHAIN096DR | 46T | Very old original chain ring (probably worn out) |
12T/13T/14T | QCHAIN098DR | 50T | Standard 3 speed Brompton |
16T | QCHAIN100DR | 50T | Standard 6 speed/Reduced gearing 2 speed |
12T/13T/14T | QCHAIN100DR | 54T | Increased gearing 3 speed |
15/16T | QCHAIN102DR | 54T | Standard 2 speed/Increased gearing 6 speed |
The Brompton chain for A Line / C Line comes with a PowerLink to make chain removal and installation easy
All current Brompton bicycles use a 3/32 inch 8-speed chain (made for Brompton by SRAM) - Previously these 3/32 inch chains were only used on derailleur (2 and 6 speed) Brompton bikes
A: The P Line / T Line (and now Brompton Electric P Line - 4 speed) comes with a choice of the following chains:
These are 10 speed chains
Please check the following table for the correct chain lengths
Chainring size | Gearing | Chain length |
56 | 4 Speed | 106 link |
54 | 4 Speed | 104 link |
54 and 56 | 1 speed | 102 link |
50 | 4 Speed | 102 link |
50 | 1 speed | 98 link |
Replacement / upgrade Brompton bicycle chainsets / chainwheel guards and crank arms
The chainset (or crankset in US terminology) refers to the components of the bicycle which with the pedals drive the bike forwards
The Brompton chainset does not include the bottom bracket - that is supplier separately
Early Brompton bicycles used a fixed chainset where the crank arms were permanently attached to the chainring - so if you wanted to upgrade / change gearing - the whole component required changing. Very early models had a 40T chainring
In 2013 a new spider crankset was introduced - this allowed the chain ring to be changed if it was worn or if a gearing change was required
In 2015 the new spider crankset was made available as an upgrade to older bikes
In 2016 the older fixed crankset was discontinued
Brompton bikes now come with a choice of 3 chainring sizes: 44T, 50T and 54T (44T gives the lowest - easiest peddling - gearing, and 54T gives the highest - highest attainable speed - gearing)
Brompton bikes use a standard pedal thread - that is 9/16inch diameter x 20 tpi (threads per inch) - so in theory you can use SPD's, MTB flats or stick with the Brompton ones
The Brompton branded pedals are neat because the left hand one folds - so makes the bike more compact when folded and the non-folding right hand one matches it (and has the Brompton logo on the spindle)
We also like the MKS pedals - they have a folding solution and a quick removal solution - so you can still fold the Brompton to its smallest size
Brompton sprockets (or cogs) for the range of rear wheels used on Brompton folding bicycles past and present
These wheels include the following:
Brompton single/two speed rear wheel (uses a Shimano spline fitting)
Brompton Sturmey Archer BSR (Brompton Standard Ratio) 3 speed rear wheel (uses a 3 spline ISO fitting)
Brompton Sturmey Archer BWR (Brompton Wide Ratio) 6 speed rear wheel (uses a Shimano spline fitting)
SACHS/SRAM 3 and 6 speed hub geared rear wheel (uses a 3 spline ISO fitting)
Note: In 2017 Brompton have discontinued spare parts for the SACHS/SRAM 3 and 6 speed rear wheels.
44 tooth Brompton crank set - silver
50T Brompton crank set (left and right complete) - the "new" 2013 "spider" Brompton crankset
44T Brompton BLACK crank set (left and right complete) Note: Picture shows 54T chainset. Pedals not included
50T BLACK edition Brompton crank set (left and right complete) - the Brompton "spider" crankset Note: Pedals and bike are not included!
54T Brompton crank set (left and right complete) - the "new" 2013 "spider" Brompton crankset Please note: This is the all black "BLACK" edition crank set
Brompton JIS bottom bracket - for the Brompton spider crankset introduced in 2013 Note: Not compatible with the older fixed crankset
Brompton folding pedal - silver
Replacement Brompton non folding right hand pedal (silver) with integrated reflectors.
Brompton 98 link replacement chain for 3 speed Brompton with a 50 tooth chain ring or 2 / 6 speed Bromptons with a 44 tooth chain ring
Brompton 100 link replacement chain for 2 or 6 speed Bromptons with 50T front chainring, or 3 speed with 13T rear sprocket and 54T front chainring.
102 link replacement chain for your Brompton folding bicycle with rear derailleur (2 speed or 6 speed bike) and 54 tooth front chainring.
Brompton 96 link replacement chain with SRAM powerlink. For 3 speed with 12T,13T or 14T rear sprocket and 44T front chainring.