Originally Posted by
pastorbobnlnh
2 I, in both cases I'm using a SRAM Dual Drive rear hub which is set up as a 3 speed IGH and it carries a 9 speed cassette. The Cannondale came equipped with the Dual Drive and I added the triple crankset and FD.
OK, makes sense. On a full size bike I hesitate going into planetary gears for efficiency issues. On a folder you need to meet so many expectations that you must be open to more compromises.
Originally Posted by
pastorbobnlnh
I really like what you are doing with your Brompton and feel as if you are conquering its weakness at a very reasonable cost (as compared to converting it to a Rohloff or Shimano IGH rear wheel). I'm still having a difficult time picturing the "tweezer" RD. Is there anyway to provide better pictures of this part, especially when the chain is shifted across your three rear sprockets? Thanks!
I am away from the bike and will remain so for one more day. The photos will need to come thereafter. As to the costs, one might say that they pile up as I try out different directions. However without big individual commitments I can roll individual steps back and whatever is left I may move around our other bikes or sell back on Ebay.
Originally Posted by
tomtomtom123
I'm curious. Do you know the angle of the Litepro adapter for the Birdy?
Also, this adapter also appears to have the derailleur mounted 6-8mm further away from the seat tube than the Litepro versions for Dahon. But is there enough slack in the pulley to allow the cage to get flush against the seat tube?
This one also appears to be more stable.
Do you still have the same bending problem with the adapter for Dahon?
The set up seems to be more rigid than even with the Wasson mount. Indeed the derailleur ends up farther away from the seatpost, but I compensate for it a bit by rotating the mounting point backwards, shortening the lateral displacement. Also what matters is how close the cage can get to the seatpost rather than just the mounting point. Finally, for Brompton there is no advantage of getting overly close to the seatpost with the cage. For the cage close to the seatpost you need to get with the smallest ring close to the seatpost and then the ring begins to interfere with folding the rear triangle under the frame.
Again, the angle will need to wait until I get back to the bike.
Originally Posted by
berlinonaut
Great post! Small error: I did not suggest making an extra notch - I mentioned it as one possiblity, especially if you want to safe on cost. I am using a Sunrace thumbshifter on my build (and pictured that as well) as I like this better and the newer Brompton dogleg instead of your way with the barrel nut as it is cheap and works very well. Did not find it difficult to set up.
Thanks! You wrote though
Originally Posted by
berlinonaut
Shifterwise I am using an S/A SL-S30 3-speed thumbshifter on the right and a optically identical Sunrace M90 friction thumb-shifter on the left. I like these better than the stock shifters - but you can use those too: 3-speed hub shifter obviously does not need to be touched, 2-speed needs a 3rd position in the middle to be cut at the inside part of the shifter - you have to figure out the correct postition for this.
I know that you used Sunrace, but just wrote that cutting the original shifter to arrive at the desired effect is not practical.
As to the cable reversal, I went through both the barrel nut and new anchorage. At this moment it looks as if the barrel nut worked better, but this may just reflect how much testing I did with each setup. In any case, I have problems with the shifting to the middle cog being consistent. I am not sure where the problem lies, whether my cogset is tight enough, whether the cable gets caught somewhere, whether there is some latency in the derailleur itself. I will need to go over every item and I also consider increasing the lever arm for the shift cable in the derailleur.