Brompton 13 tooth rear sprocket 3mm for 3 speed and SRAM 6-speed

Brompton 13T sprocket - 3 spline 

Replacement Brompton 13 tooth sprocket with 3 splines (ISO) - for 3 speed BSR wheel

The Brompton 3 spline (also known as ISO) sprocket will fit 3 speed Sturmey Archer (not BWR/wide ratio) or  3/6 speed SRAM/Sachs rear Brompton wheels. As used on the Brompton B75

The rear side of the sprocket has a flange / step built in - this should be facing to wards the hub/centre of the wheel

Click here for more info on the complete SACHS/SRAM sprocket stack

Brompton 2020 Q part code: Q100040
Brompton Q part code: QRSPR13DR
Brompton part number: 9024049 

Here is a short vide we made on removing your existing sprocket

In 2020 Brompton have started calling this: SPRKT 3/32" 3-Spln 13 6-Spd