Great mod belinonaut! Never read about 3 cog mod for the Brompton before. Like 2_i, I too can live with the 6 speed spacing (although that 9 spacing looks awesome) but find I need lower gearing if caught in the mountains, esp with touring gear weight. My 44T 88" top gear is fine for me on this bike, don't mind coasting faster downhills and >30mph gets scary on the small wheels anyways.

I'd be happy with a plug-n-play/bolt-on smaller chainring w/manual finger derailleur, but there's not enough clearance when folded.... looks like you have to widen the bottom bracket some.

Anyone do this with a late model B.... and with the new bottom bracket (post recall)?