Mk1 sharp hump bend, in frame tube.. the collectable.. black ends red main frame


Mk2 the frame tube smooth bend, 5 speed version, used the 2 cable hub
so fittings for shifting chain, funnel nuts on hubs , and cable roller wheel on both ends..
[used to have a 3 speed , rack & bottle dynamo , black]


Mk3 the 6 speed hub was from Sachs, 13t & 15t ( skipped every 5th tooth) , but 3 spline , 3/23" thick cog,

Mas;
The Brompton Book https://www.amazon.com/Brompton-Bicy.../dp/1901464253




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