Originally Posted by
Duragrouch
Ooo, I just noticed, the rear derailleur uses one of those L cages to increase the capacity without reducing ground clearance like with a longer cage. I first noticed that on the Dahon Curl D9 (still vaporware here in the USA, a shame because it also has discs).
This derailleur cage extension is not mounted to increase the derailleur capacity but to keep the chain under tension when the rear triangle is folded. Its necessary because on the Brompton folding concept (and also on the Birdy) the distance between the crank axle and rear wheel axle become much shorter when the rear triangle is folded.
This solution of derailleur cage extender to keep the chain under tension was originally developped for the Birdy 1 and then Birdy 2 and has been demonstrated to be unreliable, sometimes the chain derail when unfolding the rear triangle. For the Birdy, several third parties components brands proposed several derivatives of this extender, none was 100% reliable.
Riese & Müller eventually developed for the Birdy 3 a totally different solution, a deformable parallelogram tensionner placed around the chainring that works very well.
Originally Posted by
tds101
Unfortunately, Litepro doesn't provide the folded size for the 20" version.
Express shipping with DPD (= Deutsche Post) won't avoid custom taxes, VAT and custom clearance costs in the UE. So the price is not much lower than a Brompton A-line which is covered in the UE by a two years legal warranty.