fietsbob

then there are 2 speed single chainring cranksets...
Some made For Brompton, not made by them..

the gears are between the arm and the chainring.

so arm rotates at a different rate than the chainring.

1.6x overdrive a 34t in overdrive acts like a 54t,

I went the other way, 2.5 :1 reduction gear, so my 54t acts like a 21.6t
and I go through my BSR gears twice , 3rd, high in low range, 4th low in high range..

both planetary, so shifts at any speed, even bogged down on a hill..

Over the bar shifter shifts easily from 1 to 3 or 3 to 1..




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