Originally Posted by
reppans
2_i, do you have a picture of the right side with the bike folded? I just realized that with the back wheel folded under, the front derailleur must be holding the chain out from/off of the chain ring?
I hope the photo below provides enough detail of interest. The chain going through the derailleur does not cause problems in folding and unfolding. On rare occasions it gets mangled in unfolding but getting it on track is not much of a deal.
By now I switched from a Brompton BB, nominal 119mm (120 in my measurement), to 116 that can be shifted laterally. I will be next looking for 113 spindle with Brompton crank on the left. My estimate is that one could go with 110 if putting SunRace on the left too. From where I am right now, it looks that one could pile there even 3 rings without compromising the fold.
Originally Posted by
reppans
The double chain ring mod looks good for riding/touring in mountainous areas viewed as low range set of 6spds/~25% steps for long uphill slogs, and a high range of the same for the flats and downhills. But for the ultimate Brompton gearing, I think the OP should do the 3cog rear derailleur mod for a low/high range 9 speed with even-ish ~18% steps...
Yes, my interest in lower gears is in the context of riding Brompton in mountainous areas. 3 rear cogs and 3 front rings will have to wait - my next priority is to convert T-bag into a backpack
