Brompton gear upgrade kit - 3 speed hub to 6 speed hub/derailleur

Brompton 3 to 6 speed upgrade kit

OK - this product hasn't been available for a while now .... why?

A short history lesson

Pre 2017

This was available directly from Brompton when life was less complicated - before the bars and shifters were changed in 2017

In the beginning - there was a choice of 1, 2, 3 or 6 speed gearing

2 speed used (and still does) a Brompton proprietary derailleur system

3 speed used (and still does) a hub gear system

6 speed uses both derailleur (2 speed) and hub gear system (3 speed) - combined: 2 x 3 = 6

Changing from 3-6 speed involved changing the rear wheel and chain tensioner, and adding the controls and cables for the derailleur mechanism

The number of combinations of cables 4 (M / H / S / P - based on handlebar type) / wheels (BWR - silver) was 4

2017 onwards

New handlebars and integrated shifters were introduced

The old derailleur shifter is no longer available

The cables changed for the integrated shifters compared to the older ones

The derailleur mechanism changed (spring / dogleg controls)

Shifters and wheels are also available in a choice of black or silver

The number of combinations of cables became 6 (M old / M new / H old / H new / S / P - based on handlebar type) x 2 based on shifter type (old triggers / new shifters) x 2 (black / silver shifter colour) x 2 (wheel colour) - giving 48 possible combinations
(sorry if we mis-calculated!)

We can quote what you need - if you send us your current setup and specification by email - we may well ask for photos to help us get it right

The old kit

Included in the old Brompton gear upgrade kit was:

• 1 x rear wheel with 3 speed Brompton Sturmey Archer wide ratio hub with 13T/16T sprockets fitted. This is the double walled rim introduced in 2013 - QRW3SS-BWR
• Sprockets reference is QRSPRSTACK-BWR6 
• Derailleur chain tensioner assembly QCTADR
• Rim tape
• Chain (QCHAIN100DR) - for use with 50T front chainring (standard)
• Gear trigger (QGTRIGDRA) - this was discontinued in 2020
  
• Chain pusher assembly (QCHPUA)
• Derailleur spring set and dog-leg (QCTSPGTRIGSET) - this was replaced by a different model in 2017 with the introduction if the integrated shifter

Summary of upgrade

The upgrade involves replacing the wheel, replacing the chain tensioner with the Brompton derailleur version, installing the chain pusher (effectively the derailleur for the Brompton), the derailleur gear cable and the shifter / trigger

In addition to this kit you will also need the gear cable - this is ordered seperately as there are 4 models depending upon the handlebar type (M, P, H or S) - these can be ordered by clicking on the "accessories" tab.

Brompton Q part code: QDRRETSET3->6BWR
Brompton part number: 9012091 

Note: Full (quite complex) instructions are included. If you want to check out in advance, please ask by clicking here. Or click on the download tab.

Frequently asked questions:

Q. Will this kit fit any Brompton?
A. No - this will fit Bromptons made after 2002 when the rear derailleur system was introduced
Please note: This will only fit newer (though 2002 is not that new any more!) Bromptons with the brazings in place to accept a 6 speed gear configuration - we will contact you to check before shipping.

Q. I am not sure of the age of my Brompton - is there a way to check compatibility.
A. Bromptons built after the introduction of the derailleur system have a hexagonal shaped fitting on the rear triangle. If you look at the document in the download tab, you can see in figure DR1 on page 2 what it looks like. If it's not on your Brompton then there is nowhere to fit the derailleur.

Q. I don't have the place to fit the derailleur to - is that the end?
A. If you still want six gears then it is possible to change the rear frame/triangle for a  new one - though this is a dealer only fitting option. 

Q. I already have a Sturmet Archer wheel - can I just upgrade the sprockets and derailleur without the wheel?
A. The BWR wheel has different gearing (the standard ratio gearing means that even if it were possible to add more than one sprocket then the gears would in effect overlap - meaning you wouldn't get the benefit) AND the driver (where the sprockets sit) is not wide enough for more than one sprocket.

Q. I have a 3 speed SRAM / Sachs wheel currently - is this kit compatible.
A. Yes - although it is also possible (normally) to upgrade the existing Sachs / SRAM wheel to 6 speed without the need for a new wheel - though the wheel is probably very old by now so the full upgrade may we worthwhile, and this 6 speed gives a wider range of gears than the SRAM / Sachs equivalent.