https://www.thorusa.com/dahon/accessories/special.htm

I guess Thor felt funny about discussing his products. But it certainly makes those models a lot more attractive.

I think that is new, I dont remember seeing that before.

Very cool. Since the Mu and the Birdy have the same size tube, it should work for the Birdy as well. If anyone gives it a try, please post. The biggest problem I see is that the chain will fall off when folded unless a double chainring guard is on the bike.

(I don't do enough hill riding to use a 34 tooth ring in the back, let along a front derailleur.)

They are brand new - Thor was still waiting for them just a few weeks ago. I think he hasn't even had the opprtunity to post here about them!

Maybe there is something I am missing...
why exactly would the chain fall off when folded?

cheers

PS. anyone care to speculate if these would work on a Helios?
What's the difference between the two? Should be approx. same diameter, same seat tube angle... looks like just a slightly different "arm" on each unit to accomodate the derailleur...

My fault for being unclear. The chain would fall off of the Birdy without a guard because the rear wheel folds under the bike and leaves the chain slack. That wouldn't happen on a Dahon. (However, the chain can fall off when you are riding it b/c the rear stay is so short. My old Mu Sl would autoshift when I hit big bumps in the road.)

This is great news but it sounds quite expensive. You would need a new crank, chainring, bottom bracket, cables, shifter, derailluer and hanger! Would anyone care to estimate?

That's a good point... in my Yeah's case, I had everything ready and was in the process of cobbling my own bracket which I didn't get to work. So all I would need is that thingie. The Swift may be able to use one as well...

Dahon.Steve :This is great news but it sounds quite expensive. You would need a new crank, chainring, bottom bracket, cables, shifter, derailluer and hanger! Would anyone care to estimate?

The red spacer ring will move the Bottom bracket out, you use your old crankset just add a chainring to it, no need to buy a new rear derrailleur either ... one could use almost any shifter .. I am thinking of a small old style thumb shifter for example .. looking at ebay right now to buy a shimano front derrailleur ..cheap one should do the trick , doesnt need to be dura Ace ..lol

thor

But you could get away with a narrow cassette in the rear.