The Dahon is now 53x18 fixed gear!!! 
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The Dahon is now 53x18 fixed gear!!!
[CURRENT PICs above!!!]
The Dahon is now tricked out with red Ourty mtb grips, a mtb brake lever, stock Dahon seat and Cannondale big seatbag, and a bmx wheel with an 18t track cog. Running a 53t front chainring on 170mm road cranks. So far this has been all around and even to MA as a fixed, where it survived Brookline's streets and trolley cars.
SPECS of the folding Dahon:
Frame/fork: 4130 folding Dahon cromo steel
Wheels: Stock 20" front, GT bmx rear with 18t fixed cog screwed on in place of freewheel
Tires: Stock front, wide "flatland" rear
Brakes: Stock front w/ one caliper replaced
Seatpost: Stock
Seat: Dahon
Grips: Recycled Oury mtb
Brake lever: junk find mtb
Pedals: stock folding -- for now
Cranks: 170mm off of a Trek 1000 w/ 53t chainring
Shifter: NONE! Derailiuer: NONE!
Got this last year for the daily commute. Train wouldn't let me take a full-size bike and the office didn't have room to store one. Gotta cool rack and fenders.
I upgraded it with a bigger front ring and better shifter, then recently ditched the gears all together, and converted it to a fixed gear. Then a few days later I modified it further, replacing the Brooks seat seen above with amore comfortable Vetta, raising the seat a third of an inch to get better leg extension, and removing the rear brakes. I also removed the rack as until I lose weight it isn't in my mind to carry a lot of stuff on a folding bike. On 10-30-05, I touched up some rust spots I found removing the rear rack, where one of the bolts has chipped the paint. I then put a vinyl washer under the bolt so the metal wouldn't scratch the frame again. As soon as I can dig up a few more washers I shall do this to all the bolts just to be safe.
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The Dahon as Dahon (before being fixed): The bike: This is the bike a secret agent would own. Remember that James Bond movie where Sean Connery took a helicopter out of several suitcases and had it put together and flying in minutes?
The Dahon folds in seconds, I'd say half a minute or so, and can be easily carried aboard a train, bus, or taxi cab. You can put it in a car truck, stow it behind a chair at home or your desk at work, and if you get a flat and have no spare, there's no rolling a cumbersome bike along -- you just fold it up and throw it in an oversize knapsack!
I had been promised an ancient 3-spd folder by a friend's brother when I was in college, but his folks sold it while he was away at a [Doh!] yard sale.
Nevertheless I have always wanted a folding bike -- a bike that really could come with me anywhere. It is more than the fascination with new and interesting cycling gadgetry... So this is my fixed gear Dahon story....
I decided to buy this thing without ever riding it.
The unfamiliar ride quality during my first test ride almost discouraged me. After a few days I noticed how the smaller 20" wheels handled really nice and sharp and began dreaming about dirt roads in peaceful woods and a set of old BMX tires.
But it wasn't until after nearly a week of ownership I truly began to appreciate how amazing it was to have a "portable bicycle".
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The package: Dahon B6--
Mine came with fenders and a rack, so all I had to do was add bar ends and slide the seat further back. I added clip-on lights front and rear and less than a week later went to clipless pedals, which was an improvement. Only other modification I did was remove the front head badge [it was glued on so no sweat!] and put a Topeak bag on the rear rack.
A nice touch are the stock fenders as well, and the chainstay bridge, which is drilled for proper mounting of a kickstand [provided with bike]. The kichstand the bike comes with is smooth, sturdy, and well finished, even having a rubber tip to avoid scratching when in use.
Then, no longer working where I needed to commute by train, the Dahon sat mostly unused. Until... Last week I found a cheapo folder ss in the trash, turned it into a fix. But the cottered cranks, etc. I don't have time to upgrade now. The result? Took the rear wheel and installed it on the Dahon. The vertical rear dropouts made chain tension a bitch, but a bmx chain and "half link" combined with 53x18 gearing proved perfect. The chain is tight -- very tight -- but loose enough the rear wheel spins freely. The fixed cog is screwed on the bmx freewheel... no lockring yet tho I might improvise one out of a bb lockring. Other additions: a tiny bell to ward off brain-dead pedestrians, I just got tired of cursing at 'em.
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[My folding bike]
For those interested in the pros and cons of the machine, here goes...
A review: After the New wears off--
The Bike: For those considering a folding bike, it is a really neat machine for little outlay, and it feels like a solid ride. However, the Dahon is not a performance-minded machine by any means, and unfortunately, you cannot adjust the handlebar height. This is a big deal because the handlebars of a bike should really be no higher than the seat; I am used to mine being a bit lower, as on my Trek XO1; even with its angled bar stem, the flats of the drop bars on the Trek are about a half inch, maybe an inch lower than the seat. If you ever tried to pedal standing up, such as while accelerating from a stop or going up a hill, on a bike with handlebars that are too tall, it is not fun or comfortable. This problem is sometimes encountered with the Dahon. But then again, it isn't intended for fast riding, and the more "upright" ride position is intentional. It will, however, take most riders used to road bikes, like myself, some time to get used to.
Indeed, my only criticism of the bike is handlebar position, but this cannot be helped greatly as the handelebar setup had to fold between the two ends of the bike when it is collapsed. If this were not the case, a pair of drop road bars would be an imporvement! However, a short pair of bar ends, slightly angled, give one a little more reach, more or less correcting the issue, and feel much better riding, without impeding folding.
The ride: The Dahon is stable, and its wheelbase, even with the small wheels, is almost that of a regular bike. It is possible to safely [without going to min. insertion marking] raise the seat to the same level as on one's road bike for proper leg extension. But one should mark the spot on the seattube with permanent marker or something so that when folding the bike and collapsing the seatpost, you don't find yourself opening the bike up and fiddling with it to find the right height again. The Dahon turns fine and you can even lean into turns [not like you're in Le Tour, but lean nevertheless] and the rack on the back is the right size for carrying a knapsack, or a bike-specific pack. Presumeably you could fit panniers, though I have not tried, and I imagine the side on which the bike folds would have to be packed with minimal items if you did fit them.
Descending and ascending hills is not as easy as on a road bike, but no chore, although you kind of which the bike had clipless pedals. I am so used to the SDPs on my Treck XO1 and Panny fixed gear that my feet slipped off several times on descents. You could fit SPD pedals, as they are short and would not impede folding, but the heavy-duty plastic pedals the bike comes with are so cool-- they fold up against the cranks! [I have, however, since fitted SPDs to this bike.]
The bike was twitchy on out-of-the-saddle riding at first, a short burst was okay but the ride becomes wobbly, partly due to the tiny wheels and partly due to the narrower handlebar and higher bar height. After a few rides one gets used to the position. Bar ends as you install on a mountainbike can solve this problem to some degree; "cow horn" or bullhorn bars as my Panasonic fixed gear has would be even better, but removing the stock handlebar is a hassle due to a stop pin that is part of the folding mechanism. With bar ends the bike is stable enough and you don't usually go faster than like 15 or maybe 17 on it anyways; I have yet to install a cyclocomputer. ecause it is intended as a commuter or a easy-to-transport bike for vacation cruising around town, it is not really meant to go fast, tho I'm pretty sure on one downhill stretch I got it up to 20 mph with no ill effects and it felt perfectly stable. The braking is as good as the riding, with V-brakes [er, liner-pull brakes] front and rear. However, the front brake, when applied, does cause some "jiggle" in the front of the bike. But this is minor, and those concerned can use the rear brake as a primary; the V-brakes are stout enough that one can rely mainly on the rear brake and use the front for control, reversing the normal braking proceedure with no decrease in safe stopping.
The stock tires -- wider than a 700x23c road rubber -- are not only good for city streets and around town riding or commuting, but also make the bike passable on gravel and dirt paths, though I've been warned not to use it as a mountainbike and take it off-roading due to the folding frame mechanism.
[Me and my Dahon!]
The above pic taken when the Dahon was new... All I did was add bar ends, removable lights, and a Topeak bag on the rack for carrying stuff. Oh, and since these pics were taken, I added SPD clipless pedals, compact lights, and a bell [I know, its corny, but it is a heck of a lot better than shouting "Outa' the way, you #$%!". And the bell is so tiny it is barely noticeable, visually.
I have been riding with the black bicycle-specific pack mounted on the rear rack; I have used this instead of my backpack when commuting to work. Use of spray on Bosheild protectant reduces the risk of rust, and protects the hinges and the frame, which shows a gap that exposes the interior of the frame tubing when when the bike is folded.
After an absence from not riding the bike daily, due to a shoulder operation, I got back on it February 11, 2005. I still love this little thing. I have had to do some maintenance; adjusting the brake cable, reinflating the tires, and relubing of the chain and derailier;rear cassette. The hinges had worked loose a bit, so using a wrench I tightened the throw of the hinges by turning the octagonal strut that comprises part of both the handlebar hinge and the frame hinge. The bike is now solid as a rock. the slight wiggle I noticed when the bike was new -- which had become worse after heavy use -- is gone.
Bombing down the street in Newark this morning, in a brisk 30 degrees, I felt like a surfer riding a wave of traffic. The once twitchy ride now feels nimble; the seating position is easily adjusted to, now; and the tweaked shift cable doewsn't skip gears as the bike did after a few months of riding caused it to be "broken in".
The verdict: Still kickin'. This bike is still a decent value for the money, very fun, and totally convenient.
On October 11, '04, this bicycle carried me safely thru the streets of Newark from the train station on its first commute, having been carried easily and without hassle on board the train. Everyone in the office was fascinated by a folding bicycle, as it was stowed under a desk at work! I unfolded it to show them how it worked, then stowed it away again. People asked what it was and where I got it. I own many bikes but this little ride is among the coolest!
There was little room for it on the train, as it is not the smallest folder out there, and trains are not bike-friendly, even when the bikes are the permitted folding kind -- but it fit easily in front of my legs in front of the seat. Not comfortably, but I easily sat throughout the 30-plus minute train ride. Unfolding took moments; it took longer to remove my helmet which I had stuffed inside my knapsack! Heading down the street whilst being followed too closely by Newark traffic, I found myself riding much faster than I had believed the bike capable of, with remarkable stability.
Folding: The Dahon folds simply and quickly, the only trick being to rotate the cranks so they do not get jammed between the two halves of the bicycle. Once folded, a magnetic catch holds it and prevents it from swinging open; those who want to be extra safe can easily secure it folded with a toe clip strap, which most older cyclists have in storage from the days before clipless pedals. When folded, the Dahon lifts easily though it is not tiny, it will easily fit on a train. I have seen others carry theirs by the seat and that is what I do, you can grab under the back of the seat like a handle and lift. With the front of the folded bike lifted, the rear wheels will roll if you pull it forward, so you don't really have to carry it until you come to stairs, etc. However, it will not roll backwards!
NJ Transit forbids full size bicycles on rush hour trains but is required to permit those carrying folded bicycles, and the Dahon performed its train test admirably. None of the above will be altered by the bike's conversion to fixed gear. In fact, it has improved.... more nimble, more utilitarian, way cooler...
[007, your bike is ready!]
The Dahon not only makes a good commuter, but a good "extra" bike for those like myself who already own several bicycles and are more or less running out of space! Plus, the upright riding position is great for those not used to the drop bars of a road bike, and the seat can be easily lowered much shorter than a traditional bicycle, making it the perfect "loaner" for shorter people who stop by and end up wanting to ride with you. Ever want to go riding with your girl and all your spare bikes are too tall? This could be the answer.
Going on a trip? To college? The Dahon would make an excellent dorm bike -- after all, no one wants to park their bike outside for four years. With the Dahon you do not have to.
Going on vacation and want to pack a bike? No need to invest in a roof rack. Spend it on a folder instead!
I own other bikes, some much more costly, others, much faster. But none are quite as neat, unique and loveable. 
People gather 'round as ask questions all the time. "Why are the wheels so tiny?" "Is it safe?" "How do you fold it?" While riding home in Newark, I was accosted by no less than 3 people interested in the bike. Even people on the train platform seemed curious. Their curiosity is well-founded. One of the attractions of the bicycle is the freedom of movement it gives its rider. What could be more in keeping with that than to hop off a train as a pedestrian, unfold your 007-style bike, and ride off down the street as a cyclist?
In all, I am growing increasingly fond of this machine.
Winter riding?
I ride this thing in the winter. General rules of cleaning and lubing moving parts apply, but take care because it is a folder, to also protect the hinges.
I ride my Dahon in winter weather as well as my regular bikes. I have put hundreds of miles on my bike [Dahon] and the paintjob and parts are still very good, tho not "like new". I have sprayed it with protectant and take time to clean it after every ride. I have to be particlarly careful because when folded the interior of the frame is exposed.
But since my Dahon has fenders, it helps to greatly reduce road grime in the first place! Steel or aluminum? I prefer steel, esp. on a "folding" bike, even with the weigth difference. Aluminum may be lighter but I trust steel more as I am 190lbs and carry a full pack on my rear rach every day to work. Within limits of the bike, it becomes a personal preference. But whatever you choose remember that Aluminum can "rust" too, though not like steel, it does oxidize and corrode over time if exposed.
Basically, whichever you get, clean the bike and put a protective coating on the aluminum parts, exposed bolts or screw-heads, spokes and hubs. Also the derailieur mechanism, if it has gears, and hinges. Thereafter, clean it after every ride, and at least once a week wipe down and relube the chain. In particularly bad weather or particularly heavily salted roads, clean and relube the chain right after the ride.
I use Boeshield t-9, but there are lots of weatherproofing products out there. Also neglected, but important, are pedals. if you use clipless pedals [i use SDP's] clean and oil or spray with protectant the mechanism incl. springs. Once the frame is sprayed [make sure the protectant you select is safe fer paint and not just plain metal!] a quick wipedown thereafter postride should suffice.
You may want to get one with internal gears, or do what i did and convert a "fix". If not, your biggest "foul weather" problem will probably be with the gear mechanism because it is so low to the ground. I know the new models have a special short derailieur but mind has a basic full size one and gets hit w/ all the road grime. One of these days I am going to either get a fixed gear 20" wheel, or an internally-geared rear wheel.
An' don't forget ride/handling. You may wanna use semi-knobby or even bmx-type tires if you intend to ride when the streets are particularly snowy.
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Read an abreviated review of the Dahon B6 by me at http://www.roadbikereview.com/2003,Folding,Bike/Dahon/PRD_139317_4344crx.aspx#reviews
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