Folding Bikes - My Dahon Mu Duo - a blend of old an new

Even though I like my 2009 Dahon Mu Uno a lot, I can never just leave well enough alone.. the original platform is minimalist and highly functional.. single speed, coaster brake, no cables at all to the rear.. horizontal drop outs, narrower rear spacing than most Dahons at 120mm .. the bike is stiff, folds easily, folds narrow and rolls when folded if you want, as the rear wheels are almost parallel to each other when the magnets clamp down.. stock, the gearing is about 65".. this covers a surprising amount of territory..

So what options are out there if someone wants to tweak the drivetrain, while maintaining the integrity of the original platform .. a Schlumpf drive would work, but the 1.65:1 overdrive is a pretty large step (as seen on the 2 speed Stridas). Moulton have a new model (the 50) with a Sachs Duomatic kickback 2speed + a Schlumpf Speed Drive .. after working out the ratios and how I would need to shift to get them, I passed on that thought and was considering just the Duomatic.. after finding that Sachs produced a somewhat rare Automatic Duomatic with coaster brake, and that I could get a NOS unit from a German supplier, I decided that was the route I would try.. since the Automatics are NOS with really old grease from the 60's, the supplier insists that they should be disassembled, cleaned of old grease, and re-lubed.. so that's what I did.. since I like 451 wheels more than 406 on un-suspended bikes, I laced the Automatic into an ALEX R390 451.. and laced up a matching wheel for the front.

How's it work in practice? Well, in a word, terrific! .. the Automatic has the same 1.36:1 ratio as the kickback Duomatic, so I have a 54" low and a 74" high.. pretty much perfect.. I get up the hills that I couldn't with the stock Uno and my comfortable cruising speed is up a few mphs.. 100rpm gets me around 21mph.. the hub shifts by centrifugal force.. the shift point is adjustable by varying spring tension inside the hub .. as stock it shifted at around 8 to 9 mph.. too low for my project.. I changed the shift point to just over 13mph (at around 80 rpm cadence).. this works out great.. the shift up is positive and fast .. the harder you pedal, the faster the shift.. if you have pressure on the pedals and are below the shift point (as in standing going uphill) the Automatic will not downshift until you release the pressure.. I can't believe how good this hub is.. I hope it lasts a long time.. here's a couple of shots.

http://farm3.static.flickr.com/2522/3993619833_3e86ef2998_b.jpg

http://farm3.static.flickr.com/2433/3994384388_2d9e0fd3b0.jpg

http://farm3.static.flickr.com/2526/3993620943_32944517e9.jpg

http://farm3.static.flickr.com/2586/3994385302_cd9a5f4635.jpg

Bruce:

You are the Master! This looks like a fantastic setup! Simply elegant, yet much more functional. Looks like a million dollars with the sleek, uncluttered lines. The Auto Duo sounds fantastic (how much do they run?) The 451 wheels look great too.

Wow. Dahon ought to make a model like this. Bet they could get lots of money for it.

Very nice.

I've been told that no bike is perfect. This must be as close as it gets. :)

hi, this is exactly what i have been thinking about for some time. I rode the Moulton two speed a few years ago at Bradfordunpon Avon, very impressive, but it was about 2,000 pounds even then.

Any chance you could let me have the contact details of the German supplier for the hub?

I'm in love

oh .... my
thats were the spokes were for .... NICE

soooo the suplied front caliper brake works with the new sized wheels ?

Thor

Thanks all for the interest.. this project really opened my eyes to how really well built some of the older hubs are, while still being fully contemporary .. I like the Duomatic kickback hubs also, but the advantage I see to the Automatic is never having to think about which gear you are in while braking (using coaster brake) ... and when powering up, you don't have to stop pedaling, kickback to another gear, and then press on.. you simply start pedaling harder and faster and the shift just happens, momentum isn't broken .. it'll even shift on the coast as you crest a hill, head down the other side and are at or above the shift point.. anyway, here's the site that I used to obtain a hub... the whole site is a treasure trove for hub gear lovers .. SRAM reportedly still have the Sachs machinery to build this hub.. perhaps a few emails nudging them in that direction could see brand new Automatics being available on the horizon..

http://hubstripping.wordpress.com/

oh .... my
thats were the spokes were for .... NICE

soooo the suplied front caliper brake works with the new sized wheels ?

Thor

Haha... Yeah, that's why you were getting two emails a day for a week... "where are my custom cut spokes??" :roflmao2: ..

Shameless plug for Thor.... the spokes used both front and rear are Sapiem stong and were not stock sizes and needed to be cut using Thor's Phil machine.. excellent source for custom spokes!

I had to change the Tektro long reach caliper for a Tektro short reach.. definately not enough adjustment available with the long reach units.

Wow. I still can't over this bike. Great job!

I'm thinking non-stop about the Automatic hub for my Moulton MK3 restoration. That would be a perfect match. It has an SA8 hub on it now, but a 2 speed coaster would bring it in line with the original design and clean up the looks of the bike.

I'll have to look into the specs of the hub.

Good job again, Bruce. Very innovative.

Wow. I still can't over this bike. Great job!

I'm thinking non-stop about the Automatic hub for my Moulton MK3 restoration. That would be a perfect match. It has an SA8 hub on it now, but a 2 speed coaster would bring it in line with the original design and clean up the looks of the bike.

I'll have to look into the specs of the hub.

Good job again, Bruce. Very innovative.

Oh boy!! that would seem sensational for your MK3!! .. even better if it's a separable.. can't remember which one you have... the Automatics on the site are 36 hole.. I laced mine to a 24 hole Alex rim .. the spacing is 110mm, so if you have anything close, should work a treat!

Sweet.

Dahon... are you listening?

already send them the link...lol

thor

Wow... nice, nice, nice job.

That hub sounds awesome.

Looks beautiful. The wheels are really elegant. . . so you can't use a V brake with 451 rims?

Dahon... are you listening?

I can see a Limited Edition of this bike by Dahon. They'd had to call it the BruceMetras Special, though. :D

Oh boy!! that would seem sensational for your MK3!! .. even better if it's a separable.. can't remember which one you have... the Automatics on the site are 36 hole.. I laced mine to a 24 hole Alex rim .. the spacing is 110mm, so if you have anything close, should work a treat!

Mine is not a separable. But I still like the clean lines with no brake and gear cables going to the back. Plus the rear triangle does not have braces for rear brake calipers, as the original MK3 used coaster brakes. So, this is perfect.

The rear spacing on the MK3 is 110. I currently have a 36 hole SA8 on a 28 hole rim. The Automatic hubs are 36 holes also, eh? I'll look on the website for the axle diameter in the new hub.

Thanks for the idea. I think I'm going for it!

Looks beautiful. The wheels are really elegant. . . so you can't use a V brake with 451 rims?

There aren't any V-Brake bosses front or rear on the Mu Uno .. originally, there was no front brake .. though once they started being delivered, one was offered as kind of an option in that Dahon includes one in a box, and you get to mount it if you want..

Mine is not a separable. I don't think any of the production Mk IIIs were.


Plus the rear triangle does not have braces for rear brake calipers, as the original MK3 used coaster brakes. Not a coaster brake, a cable operated drum. However they were so pathetic I'm sure many were replaced with coasters.

The hub in question was an S3B and was such a total loser that Sturmey Sunrace wouldn't name the new 3 speed fixed gear the SB3 despite the clamor for it to be named after St. Sheldon.

The 3 speed hub itself might have been OK, though I never could get mine working quite right. But the brake was worthless. Raleigh insisted that it fit into a standard diameter shell so they wouldn't need 2 spoke lengths. To complicate it being too small the braking surface was chromed and the seals between the 3 speed and the drum leaked. I brazed V-Brake pivots on my Mk III swing arm and replaced the hub with S5 guts in an alloy AW shell.



The rear spacing on the MK3 is 110. I currently have a 36 hole SA8 on a 28 hole rim. The Automatic hubs are 36 holes also, eh? I'll look on the website for the axle diameter in the new hub.

Thanks for the idea. I think I'm going for it!

It might be worth waiting for the new Sturmey S2C kickback 2 speed coaster. With expected sales of half a million a year I'd be surprised if there wasn't a 28h version for small wheeled bikes. Wonder if the 2nd gear is over or under 1:1.

I love this - I'd not heard of these hubs before - very intriguing. I just fitted a SA 3 speed onto a fullsize bike with hub brakes (rear is a back-pedal too) and it's so nice for the looks not to have all the cables everywhere. It really suits 451s too - excellent work and nicely documented too... :)

I've not heard of this type of hub before, is the model you have heavy?

I have no shame. Based on this thread, I have ordered a Duo hub from Bruce's dealer for my restored 1970 Moulton MK3. It will be so right for so many reasons (excluding the pocket book).

With the Duo hub, the look will be so much cleaner and original. I will therefore also put the original (non-drop) handlebars back on the bike.

Now, the hardest part will be the 4 year wait for the part to arrive from Germany. :eek:;)


http://i39.photobucket.com/albums/e157/sesamecrunch/MK3sm.jpg

Now, the hardest part will be the 4 year wait for the part to arrive from Germany. :eek:


are you serious about this long wait ? why 4 years ? that long to manufacture the part or that long to scrub all the used bike stores in germany to look for the part ? does the day starts counting now ?

Well done Bruce, an excellent mod.
and thanks for the info on the gears, ratios and adjustments.

are you serious about this long wait ? why 4 years ? that long to manufacture the part or that long to scrub all the used bike stores in germany to look for the part ? does the day starts counting now ?

No, I was just being playful. It will take 4 weeks, but it'll feel like 4 years to me.:D

No, I was just being playful. It will take 4 weeks, but it'll feel like 4 years to me.:D

4 weeks will fly by.. it's when it gets into the 5th week you'll start spontaneous drooling .. :lol:

Can't wait to go for our inaugural 2 speed tour of the coast.. much like the vintage 3spd English roadster tours, only 33% less gears to worry about .. :thumb:

No, I was just being playful. It will take 4 weeks, but it'll feel like 4 years to me.:D

that sounds better. one more question - how much did it cost you and where can i get this one ????

thanks,
vic

that sounds better. one more question - how much did it cost you and where can i get this one ????

thanks,
vic

Bruce listed the link in an earlier post. Prices for the different hubs are on there too.

Bruce listed the link in an earlier post. Prices for the different hubs are on there too.

Check it out, it's a great site, lots of good stuff.

Earlier I had written;

It might be worth waiting for the new Sturmey S2C kickback 2 speed coaster. With expected sales of half a million a year I'd be surprised if there wasn't a 28h version for small wheeled bikes. Wonder if the 2nd gear is over or under 1:1.

I just found out the Moulton that was shown in London with the prototype of the hub had gears of about 50" and 70". The bike has 20" wheels and in the photo it's clear that the ratio of the belted cogs is closer to 2.5:1 than 3.5:1. So therefore it's an overdrive. Good for small wheels.

http://www.flickr.com/photos/19871340@N00/sets/72157622545366532/

If the demand is high enough there could be two versions, overdrive for small wheel bikes and underdrive for big wheels.

I had the great pleasure of visiting the mad folderista BruceMetras today at his Bat Cave. What a treat! Truly a fine collection of folders with sophisticated upgrades. The man has taste, if not common sense.

The highlight of the visit was riding the Mu Uno Duo. The Uno was light and fast. The Auto hub was incredible! Like magic. Two speeds, 54" and 75" on those 451 wheels were perfect for the ride we took. It was so much fun to have the Auto hub shift automagically. Incredible. The bike is beautiful to look at too. Sleek, black and sexy - just like Bruce :D.

I also got to ride his Pacific Reach Road. Very nice bike. It was a good thing my wife hid the check book before I went to visit him...

....and why, you ask, was I visiting the mad folderista?....well, that's a story for another thread....:lol:

....and why, you ask, was I visiting the mad folderista?....well, that's a story for another thread....:lol:I'm guessing you got the Schlumpf from Bruce...

I'm guessing you got the Schlumpf from Bruce...

Nothing slips by you, does it, Jur? Yup, Bruce is quite the Schlumpf connoisseur, and has indoctrinated me as well.

The highlight of the visit was riding the Mu Uno Duo. The Uno was light and fast. The Auto hub was incredible! Like magic. Two speeds, 54" and 75" on those 451 wheels were perfect for the ride we took. It was so much fun to have the Auto hub shift automagically. Incredible. The bike is beautiful to look at too. Sleek, black and sexy - just like Bruce :D.

I also got to ride his Pacific Reach Road. Very nice bike. It was a good thing my wife hid the check book before I went to visit him...


And here I thought the highlight was you getting to see a duomatic apart on the workbench .. :lol: .. fun to break away from work for 45 minutes for that 10.5 mile jaunt .. I would have sworn at one point you were up around 120 rpm .. did you have a chance to glance at the monitor??

Boy, can't wait for the 2010 bikes to see what you buy next ... :eek: :eek:

Boy, can't wait for the 2010 bikes to see what you buy next ... :eek: :eek:

:notamused::notamused::notamused:



.. did you have a chance to glance at the monitor??


I did get up to 26mph on the Duo! I loved riding that thing. Dahon should make that a Special Edition!!!!

I did get up to 26mph on the Duo! I loved riding that thing. Dahon should make that a Special Edition!!!!

Actually, Garmin said you hit 26.9 mph .. but who's recording .. :lol:

Hello,

i found the wonderful conversion of your Mu uno, just great!:thumb::thumb:

I´ll get my Uno the next days and during winter i want to prepare a second wheelset with 451 rims and a Duomatik hub. But i was wondering about the alex r390 rims you are using. I haven´t found such ones for 24 spokes. Where did you get them? Probably i have to order anyway in US (up to now i haven´t found any dealer here in germany or europe). And what front hup you used?

For the rear hup i would like to use a 28 hole rim which fits perfect to the 28 holes duomatik. But for the front wheel i would be great to have less spokes....

Maybe you can give me some hints. Thank you and greetings from germany

LOve it!

I can dream of the carbon Ori/Mezzo Surpaz with one of these. Carbon fibre frame with 2 speed hub, 7 killo territory ? ! Ebay search saved for this hub!

Sorry more questions..
How does the sturmey archer s2c compair?
Weight saving over a typical 9 speed set up anyone?

Are you putting a carbon crank or a beam seatpost on at all ?

Hello,

i found the wonderful conversion of your Mu uno, just great!:thumb::thumb:

I´ll get my Uno the next days and during winter i want to prepare a second wheelset with 451 rims and a Duomatik hub. But i was wondering about the alex r390 rims you are using. I haven´t found such ones for 24 spokes. Where did you get them? Probably i have to order anyway in US (up to now i haven´t found any dealer here in germany or europe). And what front hup you used?

For the rear hup i would like to use a 28 hole rim which fits perfect to the 28 holes duomatik. But for the front wheel i would be great to have less spokes....

Maybe you can give me some hints. Thank you and greetings from germany

Hello my Uno friend from Germany!

I purchased the 451 rims and front hub from Bike Friday in Oregon, USA.. Their Tikit uses a narrow 74mm front hub as does Dahon.. B/F offered two grades of hubs at the time, I went with the premium hub which is very smooth and finished nicely.. I ordered the spokes from ThorUSA which are Sapim Strong, and were custom cut to size.. you will also need a short reach caliper brake for the front..



LOve it!

I can dream of the carbon Ori/Mezzo Surpaz with one of these. Carbon fibre frame with 2 speed hub, 7 killo territory ? ! Ebay search saved for this hub!

Sorry more questions..
How does the sturmey archer s2c compair?
Weight saving over a typical 9 speed set up anyone?

Are you putting a carbon crank or a beam seatpost on at all ?

Thanks for the props! ... I haven't ridden the S2C, but I would think it is very similar to the kickback Duomatic.. on a personal note, I like the look of the Sachs hub better and the machine work on the internals is beautiful..

No idea on the weight savings (if any).. my Sachs is not light, I think it was right around 950g.. I had a very lightweight SDG post and seat on it for awhile, but I stuck the heavier stock post/pump combo back in.. I even put the kickstand back on.. no plans for a crank change until I wear out the stock part.. it would be fairly easy to go sub 20lbs with the Uno if wanted.

Hi Bruce,

thanks for information. I´ll get in contct with bike friday and hope to get rims and a front hub. I´d prefer 28 spokes rear cause my duomatik has 28 holes :-)) and a front wheel with 24 or less... Hope i´ll get them...

First i was thinking about the S2C but as you already mentioned the Duomatic is about 500gr. less weight!!!!

I´m dreaming of a conversion to gates belt drive :-) Moulton offers the S2C with belt drive in the TSR2. The belt pulley should fit also on F&S Duomatik. And thorusa showed already that belt drive works on a mu frame.
But still i didn´t get any information how to get the belt pulley...

This (wheels and maybe belt drive) will be my winter project - and we will have winter here :-((

Thanks and greets
Roman (Uno)

Hi Bruce,

thanks for information. I´ll get in contct with bike friday and hope to get rims and a front hub. I´d prefer 28 spokes rear cause my duomatik has 28 holes :-)) and a front wheel with 24 or less... Hope i´ll get them...

I have a spare, new, 28h Alex 390 rim here if you find you need one and can't get one on your side of the world.. Velocity also has a nice selection of 451 rims... I used Velocity rims for my Duomatic 700 bike...



http://i181.photobucket.com/albums/x301/bmetras/IMG_1459.jpg



I´m dreaming of a conversion to gates belt drive :-) Moulton offers the S2C with belt drive in the TSR2. The belt pulley should fit also on F&S Duomatik. And thorusa showed already that belt drive works on a mu frame.
But still i didn´t get any information how to get the belt pulley...

The new TSR2 uses Delta C-Drive components, not Gates Carbon Drive .. before you start buying expensive belts and cogs, make sure and take measurements of your bike and input ratios in a gear inch calculator .. there are very few selections in acceptable belt lengths and cog sizes.


This (wheels and maybe belt drive) will be my winter project - and we will have winter here :-((
Thanks and greets
Roman (Uno)

I toyed with belt drive for mine, but never pulled the trigger.. there are new products (like the Schlumpf belt drive system), and Gates with their newest iteration .. for now, I run with what works and just keep my chain really clean (easy to do with only two sprockets)..

I have a spare, new, 28h Alex 390 rim here if you find you need one and can't get one on your side of the world.. Velocity also has a nice selection of 451 rims... I used Velocity rims for my Duomatic 700 bike...

I already checked the Velocity Fusion. I could get it in 28 hole version from a shop in UK.
Do you know if the Alex R390 is available in 28 holes - or maybe you have one :-)





The new TSR2 uses Delta C-Drive components, not Gates Carbon Drive .. before you start buying expensive belts and cogs, make sure and take measurements of your bike and input ratios in a gear inch calculator .. there are very few selections in acceptable belt lengths and cog sizes.

That i didn´t know, thanks a lot.

I toyed with belt drive for mine, but never pulled the trigger.. there are new products (like the Schlumpf belt drive system), and Gates with their newest iteration .. for now, I run with what works and just keep my chain really clean (easy to do with only two sprockets)..

I know about the Schlumpf belt system. I use a Schlumpf drive in my daily bike :-). So i always check whats new from Schlumpf...

The belt thing is more a dream, main important are the wheels and the Duomatik - and maybe a handlebar in bullhorn look. But alos hard to find in the 1" diameter in black...

Greets and thanks
Roman

Oh, sorry !

just realized that you have a 28h R390 - great. I´ll keep in mind !!

Let´s see what bike friday answers...

I have a spare, new, 28h Alex 390 rim here if you find you need one and can't get one on your side of the world.. Velocity also has a nice selection of 451 rims... I used Velocity rims for my Duomatic 700 bike...



I think i have to ask you for the 28h rim. I can get the 24h rims and hub. Here i could get the Velocity Fusion and the Alex DA22 - but only in 28, 32 or 36h.

Please let me know how to go on. Up to now i cannot sent a PM (less than 50 postings :-(( ) so maybe you can get in contact with me with PM.

Thanks

Is this the hub? I've been looking but a lot of the sources from a few years ago seem to be gone...

"Torpedo Automatic A2110 with Coaster Brake"
http://www.torpedo-coasterbrake.com/torpedo-two-speed-hub.htm

Thanks!

Have you seen the new Sturmey Archer S2? New kickback hub with a without coaster brake. I believe Nexus is also coming out with one soon. The hub used on Bruces bike was NOS.

Is this the hub? I've been looking but a lot of the sources from a few years ago seem to be gone...

"Torpedo Automatic A2110 with Coaster Brake"
http://www.torpedo-coasterbrake.com/torpedo-two-speed-hub.htm


Thanks!

Yes, that is the hub I used in both of my bike mods... to be released this year from SRAM will be the A2 .. an automatic 2 speed hub based on the Sachs unit .. reliable info has been sketchy at best ..

SRAM announced a new 2 speed automatic hub recently...

Thanks - I've been loving my Dahon Speed for a few years, but I really don't need the 8 gears and keeping the whole shifting apparatus in shape gets to be a drag.

In NYC I feel like the 451mm wheels are a godsend b/c I'm always in a pothole or on a curb, but otherwise I think your mod represents a near-perfect commute bike.

I suppose I'll spring for the Uno, and then wait for the new SRAM hub to materialize ;)