ilovebicycling

Here's a hi-res (well, bigger) of the Dahon Curl:

https://files.okbike.cn/photo/month_0...92b51effcb.jpg

Suffice to say: me wants.

DVC45

Me likey too!

jur

With a chainring smaller than the back cog , it's not going to be very useful.

ilovebicycling

I noticed that too. But this may be a pre-production model. I trust Dahon knows what it is doing and have a bit of experience building bicycles.

The picture referenced above is very revealing as to the quality of the Curl. I doubt this will sell for less than $1K.

-the folding pedals look nice (better looking than the one on my Brompton)
-it seems the seat rail "articulates" into the fold making for a more compact fold
-the integrated rear rack is very cherry

I predict this Curl will be lighter and more compact than the Brompton.

Lalato

What's up with that crazy derailleur?

ilovebicycling

I don't think that's a derailleur; it's a chain tensioner. From the looks of it, when the Curl is in unfurled, that long swingarm pivots to be parallel with the chainstay. If you picture it, that would result in a nice, clean look.

Me likey too.

csisfun

In my opinion, the Curl makes short work of more expensive Bromptons, well known for their compact fold, assuming that it has a better configuration, which usually is the case (7 speeds). The essential make-or-break features would definitely be price, for me. To me, Dahon is a great brand - for what they cost - they provide 90% of an equivalent, but more expensive, folder. The future looks bright for this Dahon.

Dahon.Steve

Holy Cow!

You're right, that's the worlds smallest chainring! LOL!

I guess you're expected to ride in 8th gear all the time, spinning like a mad man! I counted 18 teeth on that chainring which means you need an even smaller cog to get some useful gears. I don't believe Shimano makes a 9 tooth cog and their smallest is 16! So using Sheldon's calculator, here's what I got!

Inches: (21 cog, 18 ring, 170 cranks, Nexus 8, 305 tire)

8th gear --- 24.5
7th gear --- 21.5
6th gear --- 18.5
5th gear --- 15.1
4th gear --- 12.9
3rd gear --- 11.3
2nd gear --- 9.8
1st gear --- 8.0

alpacalypse

Maybe they're using a geared up hub, like the Sturmey Archer SRF8.

Sheldon's calculator gives these inches for a 21t chainring and 18t cog with the SRF8:

60.1
46.9
41.4
36.6
32.3
28.6
25.2
19.7

That's still a little low, but with a slightly larger cog it wouldn't be that ridiculous.

kamtsa

From the picture its seems that there is not room for a larger chainring.

Possibly they have a larger gear ratio in the hub.

Kam

gringo_gus

how does one hold/move it folded. Better saddle fold is neat, but can the saddle still double as a handle?

vincentnyc

we all know how it look folded...but how does it looks unfolded? that is the million dollar question.

bhkyte

needs adatchable crank arm,or a special very high geared internal hub. Achiles heel of low gearing seem envitable.

brakemeister

maybe it has a geared bottom bracket a la schlumpf
OR a very special geared rear hub

KitN

The fold of the Curl still looks messy and no where near as neat and compact as the Bromptons....

invisiblehand

Hmmm, I wonder whether there is a lateral displacement that would allow a bigger chainring. Alternatively there might be a planetary gear in the BB/crank.

brakemeister

nobody will be forced to buy one ...

even if the fold is more compact ( ie smaller )

about " messy" that most likely depends on the owner ..... I havent associate messy with any folder .. they are usually pretty well housetrained ... unless you drive them through the mud....
and yes Brommies float over the dirt and never get messy ... lightweight as they are


enter a liberal amount of smileys into this post as it is obviously a hefty amount of sarkasm....
some posters have to understand that it is not one company against another, its us versus cars or silly rules, or stupid politicians , or this and that ... its NOT Brommie versus Dahon , or Birdy versus Downtube or anything versus ....

there are millions of causes to get active.... One folding company against each other is NOT one of them ....


thor

jur

"Messy look" while folded is quite irrelevant...

$1k... I predicted a while ago (before the economic woe) that you'd be looking at no less than $1.2k. Now, I think $1.5k is probably a minimum point.

Unfolded, it looks weird due to a snaky top tube. It snakes from left to right to accommodate the wheels when folded.

I suspect the reason why we haven't seen them properly is that small chainwheel problem. In the prototype in that pic, the chainwheel problem was insurmountable, so a small one was all they could fit in. The patent drawings also show a small chainwheel, so it would seem a very very tough problem.

With a Schlumpf and a SA-8, it's going to drag quite a bit. Plus the price would be $2k+... things could be simplified a bit by not making the BB a Schlumpf, but a fixed step-up. But the chain wear would be very quick indeed with sprockets that small. I hope they designed in a replaceable front sprocket.

I hope all these problems are/have been tackled and solved by a team of competent engineers, not the art students who came up with some of the more memorable "features" of Dahons of late.

>>ECB<<

Notice how that front sprocket seems to be eccentrically mounted, though? I suspect there's more going on there than meets the eye....

ECB

ChiapasFixed

woah, crazy!
any news from the Taipei show?

tcs

This picture of the Curl with normal chainring is all over the 'net, folks. Scheesh.



BTW - that's not a "derailleur" - it's a chain slack take up for the fold, much like the Brompton has.

tcs

jur

I am well aware of that one which has been around for quite some time. That bike though has not been seen since, leading me to wonder about whether it actually works.

So the question is, which one is more recent? Do you have privy info which one is closer to production? Why put out a bigger pic of a bike WITH Dahon logos, with a smaller chain"ring", if there wasn't an issue?

ilovebicycling

In the photo from the 1st post there is considerable slack in the chain at the bottom. A bigger chainring will pick up that slack quite nicely thank you. Surely this isn't a final form for the curl and Dahon might be keeping some things close to the chest until all the kinks are worked out.

invisiblehand

The potential problem is whether the chain stays leave room for a big chainring when folded. At least that is my take on the discussion and what my comment is in reference to.

kamtsa

All those chains, chain wheels and cogs add a lot of complexity to bikes, especially in folders. I wonder when we will see a direct drive foldie. For example, something similar to this:

https://bobs-bikes.com/images/library...le_ma_06_m.jpg

but with only two wheels and an internal gear in the front wheel (similar to those gears that you can put in the bottom bracket, don't remember who makes them).

Kam