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Dahon’s Flatpak Design Allows New IOS D9 to Fold Fully or Flatten Out

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Dahon Flatpak technology width diagram

As a leading manufacturer of folding bikes for over 30 years, Dahon didn’t just create one folding system and use it on all their bicycles, but instead have continued brainstorming to produce a few different designs like the nearly invisible lockjaw hinge that Bikerumor recently previewed. One of their other innovations is Dahon’s Flatpak technology, which allows a bike to quickly fold into a narrow shape with the handlebars turned and pedals removed or flipped up.

The Flatpak components are equipped on some non-folding hardtail models from Dahon, which provide similar advantages to the aftermarket Flipcrown system. The IOS D9 bicycle goes a step further by employing the Flatpak design and components, but still folding down fully for even more compact storage or transit purposes.

Click below the break for photos, info and specs on the IOS D9…

Dahon Flatpak technology, steps diagram
In six steps, Dahon’s Flatpak bikes can be whittled down to a width of approximately 7″ for squeezing into narrow spaces like hallways, storage lockers or even beside your work station. The stem features a quick-release handle which is flipped up to allow the handlebars to rotate side-to-side freely and rest against the bike. The handlebars can also be rotated so your brake levers face down and don’t protrude outwards.

Depending on the model, the bike’s pedals are either removed via their quick-release connections and stowed in a holster on the seat mast, or folded up as on the IOS D9. There is also a tab under the down tube that holds your front wheel straight while the bike is in flat mode.

Dahon IOS D9, fully folded position

If the Flatpak design still isn’t small enough for your needs, the folded dimensions of the IOS D9 are 30”x17.3”x34.3” with the frame collapsed.

As for specs and components, the IOS D9 features a hydroformed Dalloy aluminum frame with Dahon’s forged lattice hinge and V-Clamp technologies. Dahon has spent years perfecting their mid-tube lattice hinge, which is light in weight but strong and durable. The V-Clamp is used on their high-performance bikes, and employs brass and stainless steel bushings in a design that locks solidly on a large, flat surface.

Dahon IOS D9, side view

Although it’s considered part of Dahon’s recreation collection, this bike is outfitted with some performance oriented componentry. The handlepost is a forged aluminum unit with a 35mm dual clamp offset stem system. The IOS D9 also features an aluminum fork, larger 24” wheels versus the often used 20’s, high pressure Schwalbe tires, mechanical disc brakes with 160mm rotors, and a nine speed Shimano drivetrain with trigger shifters. The complete bike weight is listed at 28.7lbs.

The IOS D9 comes in sable with gold accents. It sells for $1,099.00 USD, and is available at Dahon dealers across North America.

dahon.com

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yogibimbi
yogibimbi
9 years ago

you lost me at “28.7lbs”

Jason
9 years ago

Here is a Flatpak video: https://youtu.be/FqKxdpa0n5g

How do I purchase the stem?

AlanM
AlanM
9 years ago

@yogibimbi, what do you expect from a bike that has to be overbuilt to be strong enough to fold, and then also have the bits and pieces that allow the folding?

charlichin
charlichin
9 years ago

My Dahon Mu Uno weights 9,5 kg. Even with the wheel size and drivetrain difference, 28,7 lbs seem a bit too much.

Peter
Peter
9 years ago

@charlichin: Dahon’s listed mass for the Mu Uno is 10.9 kg. I’m not saying yours isn’t 9.5, but they advertise it at about 1.5kg more than you’ve measured. Perhaps they’re high-balling the mass of the IOS D9 as well?

Daniel M
Daniel M
9 years ago

They lost me at aluminum fork. Ouch.

Patrick
Patrick
9 years ago

A folding bike for $1100, and you’re complaining about 29 lbs and an alu fork? What do you expect?

Charlichin
Charlichin
9 years ago

@Peter, my Mu Uno is lighter because I have removed the rear rack, swapped the pedals, the saddle and the handlebars, so the comercial model weight should be close to the one listed by Dahon.

Dylan
Dylan
9 years ago

You lost me at aluminum frame. There could not be a worse material for unsuspended bicycles IMHO.

wildgrok
wildgrok
9 years ago

this bike looks good to me overall: 24″, good weight for the price

Victor K
Victor K
8 years ago

Exactly three months ago I bought a Dahon IOS 9. The intention behind this “upgrade” from my beloved Mu Uno was that I had decided to start commuting to and from work, a manageable 10-mile ride in each direction. The Mu Uno is IMHO truly Best in Class but the larger wheels of the IOS and its gearing attracted me irresistibly. So let me attempt to offer a candid and entirely non-expert review of my three-month experience.

RIDE: Thanks to the 24-inch wheels, the ride is truly superb. There is just no comparison with smaller-wheel bikes, especially as much of the riverbank where I ride is paved in cobblestone of sorts and feels tiresomely bumpy and rattling on smaller wheels. The IOS rides nice and smooth on all terrains.

FRAME: The bike feels nice and “normal” somewhere between my calves. BTW, my perennial gripe about all those bikes with 16-inch wheels is that the frame feels so weirdly somewhere between my ankles, something I find rather disquieting and out of proportion. This one feels just right.

GEARS: The upper gears offer the higher speed that I was looking for relative to the single-speed Uno, so I am perfectly satisfied with the outcome. It all “translates” to greater distance traveled, of course, due to the greater circumference of the wheels, too. I go up any incline without resorting to 1st or 2nd gear.

SHIFTING: The trigger-shift mechanism is really, really nifty. It’s still a bit notchy on the downshift but that’s probably entirely my own fault; haven’t had this bike long enough to get intimate enough with it. The triggers are truly excellent and ergonomic, lightning-fast and minimum-effort.

BRAKES: The dual disc-brakes are absolutely fantastic! They will stop you on a dime each and every time you need to. Their grips are nice and ergonomic so I couldn’t ask for anything better or anything more. Hang on tight when you brake hard! This ties in nicely with my next subtopic, namely…

PRICE: Considering how frightfully expensive folding bikes with disc-brakes can be, the sticker price of $1,100 seems to me extremely buyer-friendly. In my particular case, knocking off a daily $5.50 off my commuting costs “translates” this bike to exactly 200 public-transportation-free days.

HANDLEBARS: The soft, gummy handles are a pleasure to hold and, with everything adjustable, you can shape this bike to mirror and accommodate your height, body-shape and riding habits just perfectly. The bars can be raised or lowered to a sportier position by way of a cleverly concealed, built-in Allen wrench.

FLATPAK: Here is where I jump off the promotional soap-box. 😉 Dahon’s so called “Flatpak technology” is for *long*-term packing only. If the bars could be folded instantaneously by way of a latch, OK, I would see the point, but if I have to pull out a wrench to do so, it’s clearly not for daily packing / unpacking.

SADDLE: This is one of the few cases when I haven’t had to change the saddle on a bike. This appears to be Dahon’s own product, not one of those BioLogic pieces. Insofar as any saddle can be one-size-fits-all, this one works for me. The decals match the frame nicely so I am not compelled to change it.

ACCESSORIES: Due to the design of the handlebars, you can mount a headlight smack in the middle of the bars, illuminating the road exactly in front of the front wheel. I put on a dual-halogen headlight, a saddle-post rear light and a polished-brass-trimmed bell, nicely matching the frame’s gold accents.

FOLDING: The bike folds well if awkwardly, at first. I had to get my reflexes used to the fact that the front wheel folds inwards; in other words you have to turn the front of the wheel back, into the frame, quite unlike other Dahons and many (most?) other folding bikes. It’s just an odd, unfamiliar routine.

ROLLING: This is by far the weakest point of this bike: the magnets simply can’t hold the wheels together when you try to roll the bike while folded. I have solved the problem by way of a simple work-around: once the bike is folded, I strap the fork to the other side of the frame with one of my ankle-straps. Bingo!

USAGE: If you need/want a bike for your single-mode commute (meaning door-to-door on the saddle, no trains, no buses) this may very well be the best, best designed, best built, best priced folding bike on earth, but if you are looking for a mixed-mode commuter, I would recommend some other Dahon.

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