Folding Bikes - Front derailleir on Dahon 20"

Does anybody make a front derailleur (or band on adapter) that fits on dahon type mega-oversize seat tubes? Other than that i thought of trying to mutilate one of their plastic chain retention thingies to have a braze-on type derailleur bolted to it. Anybody tried anything like that?

Pretty expensive though- new hub & wheel re-building vs a derailleur and a new chainring...

Check with Gaerlan, he does lots of aftermarket Dahon work. There's also a guy on BF named Brakemeister who does the same at his shop.

But offhand, I'm going to say it can't be done, or at least can't be done well. If it could, Dahon would've put a double on a bike like the Speed Pro / Speed TT rather than use the SRAM DualDrive.

FWIW, some other folding bikes are more amenable to front derailleurs (but are still uncommon), e.g. Bike Friday and Swift, maybe the Airnimals. Several Moulton separatable bikes also use FD's.

None are cheap. So it's possible that swapping the cassette and/or front ring may be the most economical option.

Not owning a Dahon myself, I don't know what is 'attached' to your bike in the area where a braze on would be added. However, if you have a steel frame bike it is rather inexpensive to have a braze on attached, assuming one can find someone to do the work. Just remember that your bikes paint job will be seriously marred.
Juan

There are front derailers that attach under the bottom bracket righthand shell. That should work fine. The chainline is only modded by a very small amount.

[edit]Here (http://bike.shimano.com/catalog/cycle/products/component.jsp?PRODUCT%3C%3Eprd_id=845524441762910&FOLDER%3C%3Efolder_id=2534374302050404&ASSORTMENT%3C%3East_id=1408474395181674&bmUID=1169450047939) is what I mean. may not be what you need but you see the idea.

I have double chainring on my Boardwalk 6, but no front derailer. I replaced the OEM chainring after I bent it. I shift by hand when necessary.

I have double chainring on my Boardwalk 6, but no front derailer. I replaced the OEM chainring after I bent it. I shift by hand when necessary.

i needed a granny gear so i cut-out the big ring from a triple and use the middle and granny gear ..
i also stop and change gears by hand..

You can order one from Japan

http://translate.google.com/translate?hl=en&sl=ja&u=http://www.ikd21.co.jp/ikd/items/i170.html&sa=X&oi=translate&resnum=6&ct=result&prev=/search%3Fq%3Dbrompton%2Bderailer%26hl%3Den%26hs%3DjAt%26lr%3D%26client%3Dfirefox-a%26rls%3Dorg.mozilla:en-US:official

They make clamps for Birdys as well.

Note that they are not cheap ... ~ $90-100

i needed a granny gear so i cut-out the big ring from a triple and use the middle and granny gear ..
i also stop and change gears by hand..
How do you do that without getting filthy?

I just added another smaller chainring to my 3 speed Merc. It was a bit overgeared for me at times. I just took off the alloy chain guard disk and fastened on a 44tooth on the outside of the 53. The only problem in changing ratios is that it's a dirty job if one is on the way to work or something like that. I could carry a latex glove I suppose, or even a plastic food bag.

How do you do that without getting filthy?

I just added another smaller chainring to my 3 speed Merc. It was a bit overgeared for me at times. I just took off the alloy chain guard disk and fastened on a 44tooth on the outside of the 53. The only problem in changing ratios is that it's a dirty job if one is on the way to work or something like that. I could carry a latex glove I suppose, or even a plastic food bag.

i have a boardwalk6..needed to climb a few hills..
so took a mtn bike triple and cut-out the big ring..
i quess i could've left it as a triple..
but i don't need to go fast..
yes it's a hassle.. carry a rag or something..
but most of the time i know before hand what gears i need for my ride..
don't want to spend $ on a frt derail..

i have a boardwalk6..needed to climb a few hills..
so took a mtn bike triple and cut-out the big ring..
i quess i could've left it as a triple..
but i don't need to go fast..
yes it's a hassle.. carry a rag or something..
but most of the time i know before hand what gears i need for my ride..
don't want to spend $ on a frt derail..

if i really needed a FD.. i could mod an old one and use a hose clamp..
to fit the large seat-tube..sorta tacky..
but the added weight of shifter, cable,FD
defeat the other parts i stripped off to save weight..

Yeah - I was thinking about that, but my big chain wheel is 53 teeth, so the old fd s that I have in the garage, coming as they do off ATBs won't fit. I also doubt the geometry of the frame on the merc would help me much, so I suppose a hook on a stick might serve to lift the dirty ol' chain up onto a different chain wheel.

Thanks for the reply.

Another option for manual gear changes is to fit a length of black home irrigation pipe to the upper chain run, same as they do on recumbents especially trikes. I used it on a chopper I built but that was low enough to change gears whilst pedalling.