I have been playing around with the gearing on my 2 Brompton M6R bikes, they both came with the standard SRAM hub with 13/15 sprockets and 50T chain wheels.
I found I could not keep my cadence up to match the extra assistance provided by the ebike conversions.
I upgraded one bike to the new BWR hub which came with a 13/16 sprocket set.
It slowed the cadence down in top gear but found the steps too great in the lower gears.
I replaced the 13T sprocket with a 12T which improved matters greatly.
On the second bike I decided to change from the 50T chain wheel to a 54T this also had the desired effect of lowering the cadence and maintained the closer step changes between gears although slightly increasing my lowest gear ratio.
I was helped by a link on another forum to a particularly good Brompton gear calculator which assisted me with my decisions.
Link:
Hub Gear Calculator
It can be used for any bike setup if you remove the Brompton specific tick mark.
I like the way you can change the output results to mph and then set a cadence figure.
I found I could not keep my cadence up to match the extra assistance provided by the ebike conversions.
I upgraded one bike to the new BWR hub which came with a 13/16 sprocket set.
It slowed the cadence down in top gear but found the steps too great in the lower gears.
I replaced the 13T sprocket with a 12T which improved matters greatly.
On the second bike I decided to change from the 50T chain wheel to a 54T this also had the desired effect of lowering the cadence and maintained the closer step changes between gears although slightly increasing my lowest gear ratio.
I was helped by a link on another forum to a particularly good Brompton gear calculator which assisted me with my decisions.
Link:
Hub Gear Calculator
It can be used for any bike setup if you remove the Brompton specific tick mark.
I like the way you can change the output results to mph and then set a cadence figure.
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