Originally Posted by
Tom_C
fietsbob, I think e-types can come with cable housing as part of the derailleur or on the frame mount. I think I've seen seen them as top and bottom pull too. And I think you are right, bikes designed for these derailleurs seem to have braze ons to secure them to the frame, I guess to stop them rotating around the bottom bracket?
badmother, I'm not 100% sure about front derailleurs either, looking at the clearances, there doesn't seem to be much room for another chainring. I'm encouraged by the people that have had success on these forums and around the internet though. Did you start to look into the practicalities of fitting one to the Brompton? I can't believe no one has tried this - unless people have tried it and failed and so not bothered to report on it!
After reading a lot I am under the impression that most peopel that add a second chainring in the front end up doing the "greasy fingers" shifting, or learn to "kickshift" at least from the big down to the small.
I guess most of us are more eager to report on our sucsess, that when we fail. Also I think when something is not right we do some thinking- then some thinkering- then some thinking- and more thinking until we forget about the whole project. At this point we have started planning the next project..
Are you thinking of doing this mod on a three or six speed? I can see the point on a three speed, especially an old frame with no der. option. On a six speed you would play with three shifters and shifter cables needs adjusting.
On a five speed (one cable) hub again, same as a three speed, may be worth it but use a gear calculator first and decide after that. I think I remember you only get 7 gears (becouse of overlapping) and in that case it may be better to go for a 7 or 8 gear hub. Depends on what you need and what you have.
If you only need some extra gears in hilly areas you may want to finger shift.
Remember it is a folder. If you fold it a lot and travel with it a der can easily be whacked out of position on a weekly basis, we are talking millimeters here.
Do some reading and searching (like in the Yahoo Bromptonforums) and find out what others have learnt from theyr mistakes. Keep us informed if you try it!