Brompton has spawned a number of after-market companies, their winning compact fold makes them popular in Asia,
where the apartments are small in high rise towers..

their 6 speed is 2 cogs on a 3 speed , a TW company mixes parts to offer a 5 speed hub with 2 cogs there is your smaller jumps..
the rear cog switch half steps the internal gear wider spaced 3 speed...

Putting a 2 rings on the cranks spreads the range out, it can be done with a gear box crank, greasy finger shifting , or as shown , addinga front derailleur ans shift lever..

If a company cannot keep up with the world wide demand for the bikes they make, as it is, why make it more complicated?






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