Brompton BWR 6-speed sprocket set 13/16T

Brompton BWR 6 speed sprocket set (13T/16T)

This is a kit of parts making the BWR sprocket stack for fixing to the Brompton / Sturmey Archer wide range (BWR) 6 speed rear wheel hub

Also as used on the Brompton Electric 6 speed rear wheel

Note: The BWR sprockets have a 9 spline Shimano style fitting - so will not fit the SRAM / Sachs 6 speed wheel - for that you would need the (discontinued) SRAM 6 speed sprocket stack which uses an ISO 3 spline fitting

This video shows how to remove the existing sprocket stack and install a new one

The chain required for this sprocket set depends upon the number of teeth on the front chainring:
44 teeth - 98 link chain - QCHAIN098DR
50 teeth - 100 link chain - QCHAIN100DR
54 teeth - 102 link chain - QCHAIN102DR 

We recommend changing the chain when you change the sprockets

Brompton 2020 Q part code: Q101615
Brompton Q part code: QRSPRSTACK-BWR6
Brompton part number: 9024162

Note: If you were looking for a higher gear - you could use the 12/16T combination (though this isn't strictly recommended by Brompton as it leads to some overlapping gears)

Which hub / rear wheel is the BWR sprocket stack for?

The Brompton BWR-6 sprocket stack is for the Sturmey Archer / Brompton developed hub used on the 6 speed Brompton folding bikes

Below is a picture of the Brompton BWR hub (with sprockets attached) - sometimes it is labelled Brompton Wide Ratio

The BWR is actually an internally geared 3 speed hub, but as you can see from the above picture it has two sprockets (normally 13 tooth and 16 tooth) which work in combination with a proprietary Brompton derailleur system - giving 6 gears in total

The sprockets on the BWR hub use a Shimano style 16 spline shape on the inside - this means they will only fit onto the hub driver the correct side facing you (one of the 16 splines is wider than the others)

Below is a picture of a (slightly dirty - to show it is a real one!) BWR hub driver (where the sprockets fit to) with the sprockets removed - so you can see the Shimano style spline shape. The one on the top just to the right is wider than the others, ensuring that the sprockets can only be fitted the correct way around

Brompton BWR sprocket set installation

The sprockets are held in place with a circle / C-ring

Tools required: Small flat-head screwdriver (no special tool is required)

Installation sequence

1/ Install the chain guard disc

The chain guard disk is fitted first, it is keyed so it will only fit onto the diver in the correct direction. It protects the hub from dirt coming off of the chain

Simply slide the chain guard disk onto the driver and push so it's snug against the spokes

2/ Install the 16 tooth sprocket

The 16 tooth sprocket used on the BWR wheel is keyed for the Shimano splined system - which is good as it means that you can't put it on the wrong way around

The sprocket is 1.8mm thick and has an individual Brompton Q part code of QRSPR16DR-SHMNO

There is a small triangle on the sprocket which points to the large spline - making alignment a bit easier

It is the same sprocket as is also used on the 2 speed Brompton rear wheel

Below is a picture of the 16 tooth sprocket installed on the BWR wheel

Simply slide on the 16T sprocket so that it is snug against the chain guard disk

3/ Install the spacer

The spacer included with the kit is 2.2mm wide, and is not keyed for the driver (though in the past we have seen keyed spacers)

It fits between the two sprockets to keep them the correct distance apart for the derailleur to function correctly and to make the sprocket stack the correct total width to be held firmly in place by the circlip

The below picture shows the hub with the spacer now installed

4/ Install the 13 tooth sprocket

Next on is the 13T sprocket. It is also keyed to prevent it being installed the wrong way around

The 13T sprocket is 3.1mm thick and also available as individual Brompton Q part reference: QRSPR13DR-SHMNO (Note: This Sprocket is not compatible with 3 speed Sturmey Archer hubs - BSR, AW, SRF-3)

5/ Install the circlip

Last up is the circlip (also going by various other names). It is just a piece of metal with a split allowing it to open slightly for installation onto the driver where it sits in a groove holding the whole sprocket stack in place

Simple but effective!

This is where you will need a tool (there are special circlip pliers, but a small flat headed screwdriver is sufficient)

The circlip is installed to sit in the groove on the driver

The picture below shows the circlip successfully installed - there will be approx a 5-10mm gap as shown

Now you are free to go ride your six speed BWR Brompton off into the sunset!