the BWR hub driver uses a 9 spline cog, Shimano pattern*, the BSR is still using the old AW3 cog..

Mk3 they went to Sachs, there the 3 by 2 used a thinner 2mm cog, 13t , and a 15t that skipped 3 teeth as shift gates..
did not change the 3 spline interface, just made it wider.. to fit 2..

I've been using a 15t on my Brompton BSR from that parts spares, for years..


* perhaps he crammed on a 4th cog on the BWR Driver.. I guess, There is some serious money in SF

Fremont is where the Tesla Car factory is.. ..

people can make things..





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