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Dahon IOS XL



Superbly well featured folding bike for urban duties…but it is hard to see beyond that price tag

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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Designed to be the 'ultimate urban bicycle', the Dahon IOS XL is an interesting addition to the ever growing folding bike sector. Made by folder specialists Dahon, the IOS XL immediately makes its presence felt, with its price, its weight, and the sheer number of bells and whistles that come as standard for that not insignificant price.

The IOS XL is definitely a bit different. For starters it sports 24' wheels as opposed to the 20' option favoured by many folding bike designs. The larger wheels are designed to give the IOS more of a 'big bike' ride, with handling less like that of a folder. The idea is to give the benefits of a folding bike, with the essential qualities of a full-size bike. These larger wheels are paired up with Avid Juicy hydraulic disc brakes and a Shimano Alfine 8 speed hub gear, as well as a whole host of neat details. The frame is one-size-fits-all, with adjustment in both the bars and the seatpost aimed at accommodating riders from 5'2' to 6'4' and a suggested weight limit of 105kg, so it's not an impossible proposition if you're a larger rider. The hydroformed aluminium frame has folding couplings in the middle and at the steerer tube, allowing the bike to be folded easily and effectively.

In addition to the basic structure of the bike itself, Dahon have added in some features to make the IOS XL appealing to the most demanding of urban riders. A decently bright integral Dahon Valo LED light, dynamo driven and with a stand light comes as part of the package, as does the nifty pump integrated into the seat tube. Possibly the most innovative feature that's part of the IOSXL deal though, is the dynamo driven BioLogic ReeCharge (£75 on its own) charger pack with its USB connection for charging any of your electronic gadgets with nary a plug socket in sight. The charger can easily be taken off the bike too, for away from the bike charging at any point during the day.

The Dahon IOS XL is a doddle to fold and unfold, quickly transforming into a compact package not much bigger than smaller wheeled folders. With magnetic plates to keep it folded, it's easy to transport, while the stand and fold away pedals make parking it simple too. The seat post height and bar angles are quickly and easily adjusted. It's a good few kilos heavier than most traditional folders, but although heavy to carry very far, it's not unmanageable. A choice of optional carry bags are available specifically designed to make life easier, but it's perfectly easily carried without.

Despite its bigger wheels and longer wheelbase, the Dahon IOS XL still rides very much like a folding bike, albeit with a greater feeling of confidence and control. On the flat it handles smoothly and reasonably responsively, with the Alfine hub making transitions between gears easy, smooth and effective. Power transfer is on the ponderous side, much as you'd expect from a bike with 24' wheels, a 15kg weight and a hub dynamo, but it's still got a fair turn of speed when necessary, it just takes a while to work up to it. The hydraulic disc brakes offer a reassuring level of stopping power with little effort, making it a good option for high traffic flow commuting.

It would probably be fair to say the Dahon IOS XL has been designed mostly with flattish terrain in mind, such as city streets, cycle paths and the like. On surfaces such as these it functions just fine. When hills are involved however, it's a different matter. Ascents bring to light the lack of leverage off the handlebars offered by the design. Absolutely ALL the power is coming from the legs when climbing, it's a fundamentally heavy bike and it's all but impossible to stand up out of the saddle due to the short distance between bars and saddle. For each pedal revolution there's a complimentary impact with the nose of the saddle. Handling is erratic when climbing also, due to the geometry of the bike, making signaling a tricky manoeuvre requiring advance planning and weight shifting. When descending, the bike is relatively stable, but again, steering is sufficiently twitchy to not inspire confident descending, also not helped by the transfer of road bumps and unevenness up through the seatpost.

A word on the BioLogic ReeCharge- it's a fantastic gadget, and incredibly easy to use. A great way of charging your iPhone, GPS or similar either while on the move (protective cases are available that will fasten to the bike allowing for on bike use and charging) or by making use of all that stored energy in taking it with you in your bag or pocket. That said, it seems to sit slightly awkwardly on what is inherently a city bike, presumably for predominantly shortish distance use. It's hard to imagine a city commuter using a GPS on the move, and there's no doubting the lack of wisdom in using your mobile while negotiating busy traffic, so it's hard to see the benefit. Surely a phone can be plugged in to charge at the office? It's innovative technology and would be genuinely useful on a touring bike, but seems a little like gilding the lily on the Dahon.

The Dahon IOS XL is a very competent and comfortable to ride city folder, with decent enough handling and power transfer on the flat city streets it's designed for. It folds easily and effectively and would do a great job as an everyday bike for someone with storage space issues, but ultimately £1499.99 is a lot of money for what fulfils the same role as many folders substantially lighter and costing significantly less. Yes, the wheels are bigger and the handling more like a non-folding bike, and you do get some great components and extras but it's still hard to justify the additional cost.


A superbly well featured folding bike, great for urban duties, but ultimately it's hard to escape the price, even with all the bells and whistles.

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Make and model: Dahon IOS XL

Size tested: n/a

About the bike

State the frame and fork material and method of construction. List the components used to build up the bike.

Frame- IBA Series, Hydroformed 7005 AL, patented Fusion and V-Clamp technologies

Fork- Dahon SlipStream, Puro U7 aluminium, patented Fusion technology, disc tabs

Handlebar- Kinetix Pro, flat bar, double butted 7050 AL

Stem- Dahon Andros, patented InfiniteAdjust technology, 6061 aluminium

Headset- Dahon Fusion XP+, zero stack, angular contact cartridge bearings, machined aluminium cups

Grips- BioLogic Arx, lock-on function, reflective end plugs

Saddle- BioLogic Aria

Seatpost- BioLogic PostPump+, 34x580mm, forged aluminium clamp

Seat Clamp - Dahon Turtleneck clamp

Front and Rear Brakes - Avid Juicy

Brake Levers- Avid Juicy

Front Hub- Alfine dynamo hub with disc

Rear Hub- Shimano Alfine, 32H, 8 speed

Rims- Kinetix Pro, niobium alloy, doublewall, CNC machined sidewalls

Tyres- Dahon Special Edition Schwalbe Kojak, 95psi, Qualifier Compound casing, RaceGuard puncture protection, Kevlar bead

Shifters- Shimano Alfine

Crankset- Kinetix Supra, forged 6061 cranks, 6061 chain ring, alloy CNC chainguard

Cassette/Freewheel- Shimano 18T

Bottom Bracket- Cartridge, sealed bearings

Chain- Rust Block, GST, 3/32"

Pedals- Suntour folding, alloy body

Battery- BioLogic Reecharge

Chainguard- BioLogic FreeDrive

Luggage Bracket- Luggage Socket, frame integrated

Front Light- Dahon Valo, HiLux LED with standlight

Tell us what the bike is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about the bike?

Designed to be the "ultimate urban bicycle" with everything an urban cyclist could want.

It has all the bells and whistles and urban rider could possibly want, but possibly more than you'd actually need and at a not inconsiderable price.

Frame and fork

Overall rating for frame and fork

Tell us about the build quality and finish of the frame and fork?

Very well made and with a good finish quality. Folding couplings smooth, easy to use and robust.

Tell us about the materials used in the frame and fork?

Tough, durable and lighter than if it were made from steel.

Tell us about the geometry of the frame and fork?

Very upright ride- it's a folder, all said and done.

How was the bike in terms of height and reach? How did it compare to other bikes of the same stated size?

Full adjustable, so one size fits anyone from 5'2" to 6'4"

Riding the bike

Was the bike comfortable to ride? Tell us how you felt about the ride quality.

Reasonably comfortable to ride, but very upright, felt high up even though I'm only 5'5", and quite an exposed feeling riding position.

Did the bike feel stiff in the right places? Did any part of the bike feel too stiff or too flexible?

Whole bike felt reasonably stiff, especially considering the folding element.

How did the bike transfer power? Did it feel efficient?

Sluggish power transfer on anything remotely resembling a hill, and fairly slow to accelerate on the flat, but once some momentum was going, speed was reasonable.

Was there any toe-clip overlap with the front wheel? If so, was it a problem?


How would you describe the steering? Was it lively, neutral or unresponsive? Slightly twitchy steering.

Tell us some more about the handling. How did the bike feel overall? Did it do particular things well or badly?

Overall the bike felt ponderous and slightly flighty, due to the very upright riding position.

Which components had the most effect (good or bad) on the bike's comfort? would you recommend any changes?

All quite comfortable. Adjustability very good.

Which components had the most effect (good or bad) on the bike's stiffness? would you recommend any changes?

No changes required.

Which components had the most effect (good or bad) on the bike's efficiency? would you recommend any changes?

Overall weight of bike was main problem in efficiency, and very upright riding position and geometry, making it difficult to use the bars as leverage and virtually impossible to get out of the saddle on hills.

Rate the bike for efficiency of power transfer:
Rate the bike for acceleration:

Slow to start, but better once some momentum is going

Rate the bike for sprinting:

Heavy and slow to get going. Virtually impossible to get up out of the saddle too.

Rate the bike for high speed stability:

Stable enough on the flat, but less stable on inclines or declines at speed.

Rate the bike for cruising speed stability:

No problems at cruising speed.

Rate the bike for low speed stability:

Fine on the flat but slightly less stable on ascents and descents at low speeds

Rate the bike for flat cornering:

Fine on flat corners, but watch out for the very low bottom bracket and pedals.

Rate the bike for cornering on descents:

Rider feels very exposed on descents, due to high riding position. Twitchy steering also makes cornering on descents a nervy experience.

Rate the bike for climbing:

It's not a bike intended for serious hills, and it manages small inclines just fine, but major slopes are not great. It's hard to put any welly into a climb when you can't get out of the saddle and you can;t pull on the bars.

The drivetrain

Rate the drivetrain for performance:

Smooth, reliable and no fuss.

Rate the drivetrain for durability:
Rate the drivetrain for weight:

Not a bad weight, especially when you look at the weight of the bike overall.

Rate the drivetrain for value:

Good value for a minimal fuss drivetrain. Especially when compared to the equivalent Rohloff.

Tell us some more about the drivetrain. Anything you particularly did or didn't like? Any components which didn't work well together?

Very smooth trasmission, easy to look after, with minimal maintenance required. Fold-away pedals a nice touch.

Wheels and tyres

Rate the wheels and tyres for performance:

Rolled just fine, with little resistance, yet were capable of coping with some rougher towpath type trails.

Rate the wheels and tyres for durability:

Tough and durable.

Rate the wheels and tyres for weight:

Robust and in line with the weight of the rest of the bike.

Rate the wheels and tyres for comfort:

Reasonable levels of comfort, road buzz not too bad.

Rate the wheels and tyres for value:

Tell us some more about the wheels and tyres.Did they work well in the conditions you encountered? Would you change the wheels or tyres? If so, what for?

Worked well for around town riding and even coped fine with some gravel trails.


Rate the controls for performance:

Easy to use and effective.

Rate the controls for durability:
Rate the controls for weight:
Rate the controls for comfort:

Well positioned, comfortable and easy to use. Made easier by adjustability of bike.

Rate the controls for value:

Decent spec on what's a reasonably pricy bike. Much as you'd expect.

Tell us some more about the controls. Any particularly good or bad components? How would the controls work for larger or smaller riders?

Adaptable and easy to use. Highly adjustable.

Anything else you want to say about the componentry? Comment on any other components (good or bad)

Kick stand handy, especially enabling parking when folded.

Dynamo driven battery a brilliant idea, but seemed slightly surplus to requirements on this particular bike.

Your summary

Did you enjoy riding the bike? Yes, but more on the flat.

Would you consider buying the bike? Possibly- if I lived in a city and had a surfeit of money.

Would you recommend the bike to a friend? Possibly- for a wealthy city type who didn't want to use a Boris bike.

Rate the bike overall for performance:
Rate the bike overall for value:

Anything further to say about the bike in conclusion?

A very well built and high quality bike, with plenty of innovative touches, but ultimately overspecced and overpriced.

Overall rating: 6/10

About the tester

Age: 37  Height: 1.65m  Weight: 67kg

I usually ride:   My best bike is:

I've been riding for: 10-20 years  I ride: Most days  I would class myself as: Experienced

I regularly do the following types of riding: commuting, touring, general fitness riding, mtb,

Lara has been riding bikes for longer than she'd care to admit, and writing about them nearly as long. Since 2009 she has been working as part of the review team whilst championing women's cycling on the side, most notably via two years as editor of the, sadly now defunct, UK's first and only women's cycling mag, erm, Women's Cycling. 

Believing fervently that cycling will save the world, she wishes that more people would just ride a bike and be pleasant to each other. 

She will ride anything with two wheels, occasionally likes to go fast, definitely likes to go far and is always up for a bit of exploring somewhere new and exciting. 

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