The RD I have is Shimano RD-5701. Its marketed as "med cage". Am I going to run into trouble with this? Poking around the internet, it looks like others have done this mod. After I got your response, I installed the 5701, even fully extended, it looks like its still above the rim of the wheel.

Well, is it long-cage (SGS) or medium-cage (GS)?
 

You said 'long-cage' earlier. Did Shimano make a 105 5700 SGS RD?

I did not see this thread back in January, my folder is not a Dahon so can't elaborate on that. But I can say I am using a Sram Dual Drive on my Airnimal. Someone on this forum a couple years ago suggested that the Sturmey Archer 3 speed bar end shifter will index the Dual Drive quite well. I bought the bar end shifter and find it works great. Second gear is direct drive, third gear is an over drive, and first gear is a low range for lower hill climbing gears. It takes 135mm dropout spacing, I do not know what you have.

A friend of mine uses bull horn bars with bar ends on his full size touring bike, he is quite happy with adequate hand positions for loaded touring.

First photo is of the Dual Drive, second photo shows the Sturmey Archer bar end shifter close to the camera, the Shimano BS64 eight speed bar end shifter is farther from the camera and out of focus. I use drop bars.

About a year ago I saw news that Sram was taking the Dual Drive out of production. It still is available on Amazon and others in the retail pipeline, but can't say how much longer they will be around. I bought a couple spare click boxes and a couple extra shift rods just in case these become scarce later. I have not damaged either the click box or shift rod, but they are somewhat vulnerable on the driveside so I wanted spares.

My mistake. Its a "medium" cage. I went back to look at my order from Chainreaction. It is described as "shimano 5701 Med Cage".
Do you think it looks too long in the photo?

Hi. Thanks for response. Are the bar-end shifters in the photo on drop bars?

Yes. Another photo attached.

Regarding the bar end shifters, on the Airnimal I have a lot of cable length, it is 8 feet of outer housing for the rear derailleur. All cables are full length outer housing. Thus, there is a lot of cable friction and the shifting on the rear derailleur is not very smooth. I could have shortened the cable routing by maybe a foot, but I really prefer having the cable follow the handle bars for the portion where there is bar tape.

The Dual Drive cable is about a foot shorter, that shifts great. The cable adjustment on the Dual Drive is not as sensitive as the cable on a Shimano eight speed derailleur, that is why it shifts much better than the derailleur. If the cable pull on a derailleur cable is off a half mm, the derailleur might not shift right which is why the cable friction is so critical, but the Dual Drive can easily deal with that.

I am considering switching to a Campy brifter instead of the bar end shifter for the rear derailleur. I plan to use the bike for a week long van supported tour in about a month. If I switch to the Campy brifter, I will make that change after the trip. I do not like to make a major change to the bike shortly before a trip where I would be away from home and away from my tools and spares.

In the photo, note the cables follow the bars until the cables exit from under the bar tape near the stem. If the photo is slightly confusing, I have interrupter brake levers on there too.

You should be ok...
 

Bigger tires help too...

Trying to add a double has lead me to a number of issues. I may need to scrap the double idea and look into the SRAM Dual Drive. The issue there is rear spacing. My Dahon is approx. 130mm and the SRAM hub requires a 135mm. Need to research this more; maybe they make a 130mm hub.

SRDD on Dahon...
 

...should not be a problem. I run a SRDD with a 47T single crankset and 11-36T cogset on my Dahon Dash. 19-113GI on tap.
https://dl.dropbox.com/s/5tx1fyof14k...8995.JPG?raw=1

Did you cold set it? What was the original spacing on your frame?
Also, what is "19-113GI on tap"?
How are you shifting? Grip shift, bar ends, STI?

No cold set. Plug & Play
 

It uses a solid axle which extends beyond the dropouts. My Dash is goode ole' 130mm OLD.

The difficulty with SRDD today is that it is discontinued. You can still find 36H specimens on sale, but how you will lace it to a typically 28H 406 rim will be challenging. Mine is 28H.

Well, though not a cheap route, I guess I could get a new 36h wheel.
How are you shifting? Is the only option a grip style for the SRDD?

You mean a 36H rim to which the SDRR is laced? Sure, look to a BMX rim.

SRDD shifts fine with Shimano MTB triple FDs.

I mean, what method do you use to shift your rear derailleur, the Shimano Zee. A grip shifter, a thumb shifter, etc.

Shimano SLX trigger shifter...
 

nt