More Gears For 3 Spd Brompton - What Are The Best Options?

[syklist]

My solution was to cram a Nexus 8 into the rear forks and fit a double chain ring and changer at the front. Not for the faint hearted. However, I have seen pictures of Nexus/Alfine 8 conversion done by a bike shop in London. So it might be possible to get someone to do the conversion for you.

The Nexus is a big improvement over a Brompton 6 speed whether a SRAM or BWR. It has the range of the BWR 6 speed but with much closer spacing between the gears. Plus only one changer to get all 8 gears.

You could go for a double chain ring. This would give you some more low gears. I bodged a cheap MTB front derailler to fit the Brompton frame and this works fine. However, the Brompton tension is not designed to cope with big changes in chain ring size. I works OK with the 50/34t chain rings on my bike but I have to be careful back pedalling when on the 34t ring especially if the chain/cogs are dirty.

[John Holiday]

A simple & inexpensive way of increasing gear range, is to fit a second chainwheel.
I did this some years ago & can climb almost anything!
I fitted a second smaller 38tooth ring on the outside of the existing 48tooth chain ring. It cost about £14 from Spa Cycles,with bolts & spacers.
You have to fit it to outside ,as clearances on inside insufficient.
I have to manually lift chain onto small ring,but this is easily done & you know when you are likely to benefit from lower range.
The rear tensioner seems to cope with it quite happily.