BTwin Ultra Compact 1 Second Light

List the components used to build up the bike.

Frame: 6061 T6 aluminium, brushed with smoky varnish

Fork: Single-arm, 6061-T6 aluminium

Folding & fastening system: articulated hinges with chunky quick-release levers. Magnets to hold frame together when folded

Claimed dimensions

Folded (L/H/W): 71 x 69.5 x 35 cm

Unfolded (L/H/W): 129 x 107 x 57 cm

Total load limit (bike + user + luggage):

Brakes: V-brakes

Wheels: 16-inch, single-walled, machined rims. Reinforced single-sided hubs with sealed ball bearings (the same technology that we use on our road bikes).

Tyres: Schwalbe Marathon Racer 16 x 1.50 with reflective sidewalls; Schrader valves

Rear derailleur: Shimano Sora 9-speed

Shifter: Shimano Sora trigger

Cassette: 11-28

Chainset: 170mm square taper cranks, 52-tooth chainring

Gear range: 30 to 76 inches

Pedals: plastic-bodied folding

Seatpost: BTwin aluminium 34.9mm with built-in stand

Saddle: BTwin ergonomic with handle & height markings

Stem: aluminium, folding, not height adjustable

Handlebar: aluminium, 22.2 mm centre diameter, 560 mm wide

Extras: LED front and rear lights, USB chargeable; mudguards; kickstand; USB charge cable

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?

It's a light folding bike with a very compact fold and several unique and very clever features.

Decathlon says:

What makes us special

Our dream was to give you a superpower:

the power to instantly transform your bike!

After all, who hasn't ever wished they could switch from cyclist to pedestrian to passenger in just 1 second?

It's now totally possible thanks to the patented automatic locking hinges developed by our design team in Lille, France.

Your Fold Light 1 Second will adapt to your needs in an instant.

So your transitions will become a real pleasure!

Designed for commuters who want an ultra-compact bike that they can take anywhere. It lets you switch from walking to cycling in 1 motion and 1 second!

With its 16" wheels and its single-arm aluminium frame and fork, this bike is the most compact in our range. This makes it the perfect partner for tight spaces like trains, the underground and lifts!

Easy opening / closing

It's so easy to fold up. And it takes just 1 motion, and 1 SECOND, to unfold!

Compact design

16'' wheels. Single-arm frame and fork. Take it anywhere! (underground, office)

Efficiency

Go further and faster with its 9 gears. It adapts to suit your journeys.

Lightweight

Weighs just 12 kg. Very balanced when you carry it folded up. No need to worry about steps.

Cycling comfort

Ergonomic grips. Comfortable, seamless foam saddle. 70° back position

Easy to move

This bike rolls along brilliantly when folded up! Push and steer it with just 1 hand!

Ease of use

Designed to be comfortable to hold and steer. Automatically locking hinges.

Easy transport

The handle under the saddle makes it easy to carry.

The story behind the design

To help them tackle this technical challenge, our design team turned to the experts at the Decathlon Sports Lab R&D centre in Lille, France.

This network of ergonomists, human science engineers and human body specialists helped us to find the best possible ergonomic set-up for:

- carrying

- steering

- posture

We carried out numerous tests (perception, use, fatigue) in the lab and in real-life conditions.

Incredible: unfolds in just 1 motion and 1 SECOND! And easy to fold too!

We want to make your transitions quick, smooth and easy with a simple folding and unfolding system.

UNFOLDING:

Incredible, in just 1 motion and 1 SECOND!

There's no need to touch the hinges at this stage thanks to the patented automatic locking system that's exclusive to Decathlon.

FOLDING:

The easy-to-locate levers make the hinges simple to operate.

The chunky levers have rounded edges so that they're comfortable to grasp.

Frame

6061 T6 aluminium frame that's lightweight, dynamic and sturdy.

The single-arm frame design makes the bike narrow when folded.

In fact, it's only 35 cm wide. That's 20% more compact than our 20" folding bikes.

Fork

Single-arm, 6061-T6 aluminium frame for less weight and more strength.

The single-arm fork design makes the bike incredibly narrow when folded.

In fact, it's only 35 cm wide. That's 20% more compact than our 20" folding bikes.

We've also used topology optimisation to develop a more "open" frame.

This technology ensures that we use just the right amount of material while retaining the necessary rigidity.

Fastening system

The Fold Light 1" is held in its folded position by a brand-new system.

Magnets located on the front and rear hubs hold the bike's wheels parallel.

Once folded, the stem is held against the frame by a clip system.

This clever system allows you to push your bike when it's folded, and to carry it without a second thought.

The bike rolls when folded

YES, the Fold Light 1" rolls along nicely when folded!

You only need to carry it when absolutely necessary. In other words, when you come across a staircase or need to put it in a train luggage rack or car boot.

The rest of the time, you can easily move it by simply pushing it along, even when folded.

Leave the seatpost in its raised position and use one hand to steer it anywhere, even in busy pedestrian zones (e.g. stations and shops).

Brakes

This bike has V-brakes with aluminium levers and calipers for powerful, progressive braking.

Recommendation:

your brakes will gradually wear out over time. How quickly they wear out will depend on how much you ride and how you ride.

If your brakes become too soft, and your levers end up touching the grips when you squeeze them, we recommend adjusting your brakes yourself or getting a workshop to do this for you.

Wheels

16 inches.

Single-walled, machined rims. Reinforced single-sided hubs with sealed ball bearings (the same technology that we use on our road bikes).

Tyres and inner tubes

Tyres- Schwalbe Marathon Racer.

Size: 16 x 1.50. - Light and precise, with good puncture protection to suit intensive users.

- Reflective bands on the sidewalls to make you more visible from the sides at night.

Inner tube:

- Schwalbe for excellent durability.

- Large Schrader valve.

Tips:

We recommend inflating your tyres to 6 bar to reduce the risk of punctures and to make your pedalling more efficient.

Drivetrain

You'll be amazed by the Fold Light 1"!

Its Shimano Sora 9-speed drivetrain (the same one we use on road bikes) makes it incredibly efficient, especially for an ultra-compact bike.

The trigger system makes gear changes precise and reliable.

This bike is great on both flats and downhills. It adapts to whatever happens on your ride and helps you manage your effort.

Cassette

9 speeds

Gearing: 11 / 28 teeth

- 11 teeth on the smallest cog. For riding faster.

- 28 teeth: on the biggest cog. You won't have to push the pedals too hard.

Crankset / Pedals

52t aluminium chainring with 170 mm cranks.

Folding pedals so that the bike is even more compact when folded.

Saddle

When you're cycling:

The seamless foam saddle keeps you comfortable.

When you're walking / on public transport:

The ergonomic saddle under the saddle has two functions.

- It makes the bike easier to carry when completely folded. The saddle swivels to face backwards to keep the bike evenly balanced when you're carrying it.

- You can use the handle to hold the bike and push it along when folded. Simply leave the seat post raised.

Seat post

- Made from aluminium, with a diameter of 34.9 mm.

- Marked so that you instantly know exactly where to set it to each time for the most efficient ride.

- Automatically rotates as you lower it. It's guided by 1 brass screw and 1 groove. The saddle swivels to face backwards to keep the bike evenly balanced when you're carrying it.

- Turns into a stand when you lower it fully so that the bike remains stable once folded.

Bike stability: 3 stands

- Adjustable stand with a button to adjust the length. The stand keeps the bike stable when it's unfolded (whether or not you have bags on it).

- Frame support stand that the bike rests on as you fold it and that protects the chainset.

- The bottom of the seat post turns into a stand if you lower it all the way when folding the bike. This keeps the bike incredibly stable when it's folded so that you can put it away or take it on public transport.

Bike weight

The Fold Light 1" weighs in at just 12 kg!

It's very light and incredibly easy to transport thanks to:

- its 6061 T6 aluminium frame and fork.

- its single-arm frame and fork design, making it very narrow.

- its good balance when folded.

Simply hold your bike by the handle under the saddle.

Climbing up stairs or onto the train will be an absolute breeze.

User height and maximum load

One frame size only.

This bike's geometry is comfortable for cyclists between 1.45 and 1.95 m tall.

This bike complies with the requirements of standard ISO 4210.

The maximum load it can take is 100 kg (bike + user + luggage). Above this weight, the warranty no longer applies.

Special accessories that are compatible with the Fold Light 1"

- The 16" protective cover (ref: 8610451):

can be used to cover your bike when transporting it (Eurostar, car, train, etc.). The cover comes in a zip-up pouch that you can attach to the underside of your bike's frame.

- 25L front bag for folding bikes (ref: 8735484):

for carrying all of your belongings. Clips onto the front of the bike's frame in 1 second.

- smartphone holder (ref: 8595221):

clips onto the bracket on the handlebar.

How can you carry your bags?

The bike comes with mounting points on the frame (above the front wheel).

These mounting points can be used for an exclusive bag designed by the B'Twin teams:

our 25L front bag (ref: 8735484). It can be clipped on and taken off with 1 hand in 1 second.

As it sits on the frame, you won't notice its weight and the bike will remain stable.

You'll be able to control your bike as normal.

/! When your bag is full, you won't be able to lift up the front wheel to mount pavements.

Accessories that AREN'T compatible

- This bike is not compatible with a rear pannier rack. This is because it only has a single chainstay at the back.

- Pannier racks that attach to the seat post are not compatible either.

- Child seats are not compatible

- Child trailers are not compatible

Stem / Handlebar

Stem:

- aluminium

- folding thanks to a patented system of hinges that automatically lock in 1 second

- height can't be adjusted

Handlebar:

- aluminium

- 22.2 mm diameter

- 560 mm wide

USB rechargeable front and rear lights

USB front light:

- 5-hour battery life.

- 10 lux for seeing and being seen.

- Clips onto a special bracket in the centre of the handlebar.

USB rear light:

- 6-hour battery life.

- 5.4 lumens.

- Clips onto the seat clamp. It's positioned nice and high so that you're really visible.

These lights comply with the French highway code and with German standards.

The dual port micro USB cable is supplied with the bike

Bike dimensions

Folded (L/H/W):

71 x 69.5 x 35 cm

Perfect for switching between transport modes!

You can take it absolutely anywhere, including in the tightest of spaces, such as trains, the underground, lifts, turnstiles, security gates and car boots.

Unfolded (L/H/W):

129 x 107 x 57 cm

Frame colour

You might notice "imperfections" in the colour of the green frame. This is not a quality defect, but rather the result of our design choice to use brushed aluminium and a smoky varnish. Your bike will therefore look like no other!

Maintenance / repair advice

Scan the QR code on your bike's frame or visit Decathlon's support website to find all our tips and tutorials on looking after and repairing your bike.

What is the QR code on the bike's frame for?

The QR code opens the door to a comprehensive user experience.

Scan it to access all of the information you could possibly need about your bike and how to use it.

- 1 video tutorial on folding/unfolding the bike.

- the support website with maintenance and repair advice.

- the spare parts website.

- the shop selling compatible accessories.

- the link to our services and insurance offering.

- latest news and design stories

RESTRICTIONS

/! It's important to always look to make sure the hinges on your frame and stem are locked in place before you ride.

This bike should not be used for stunts, mountain biking or BMXing.

Warranty

Lifetime warranty on the frame and stem (excl. hinge), rigid fork and handlebar.

Where does this model sit in the range? Tell us briefly about the cheaper options and the more expensive options

Decathlon/BTwin offers five models of folding bike, plus one with electrical assist. This is the top model, and the only one with 16-inch wheels to make for a compact fold. The next model down in the acoustic range is the £500 BTwin 900 folding bike, with a more conventional folding mechanism and the same Sora nine-speed gears and V-brakes.

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

The chunky welds are tidily done and the varnish-over-brushed-aluminium finish is distinctive and unusual.

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

Good old 6061 aluminium that looks to have been subjected to various forming processes to shape the tubes. Very standard stuff (the 6061 formulation is only a few years off its centenary) but well executed.

Tell us about the geometry of the frame and fork?

It's short, and the trail being short too really dominates the handling.

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

One size fits all, but the reach is very short compared even to other folders.

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

With the tyres at the recommended 90psi it's distinctly buzzy and the upright position and short wheelbase really don't help. The upshot is that this isn't a bike you'll want to ride for hours on end, but it's tolerable for short rides, and considerably improved by running the tyres at 40-50psi.

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

Fine overall, but the extended handlebar stem is noticeably flexible if you haul on it at all.

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

It's not race-bike eager but it's decently efficient.

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

No.

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

It's twitchy. That's good for swerving potholes round town, but at speed it's quite disconcerting.

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

The saddle and grips are good and help to alleviate the bike's buzziness.

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

Shimano Sora 9-speed with a KMC chain and anonymous cassette, but it all works fine together.

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

I'd be tempted to try something fatter, like a 1.75in Schwalbe Marathon or 2.0 Schwalbe Big Apple, though the latter would be a tight fit.

How does the price compare to that of similar bikes in the market, including ones recently tested on road.cc?

For several decades the folder of choice among British multi-modal travellers has been the Brompton, with its low weight and incredibly clever fold. But Bromptons have got steadily more expensive over the years: the base model is now £925 from Halfords for a bare bike with a three-speed hub and without folding pedals.

For £75 less, the Btwin Ultra Compact comes with lights and mudguards, 9-speed gearing, folding pedals and a kickstand (though the ability to fold a Brompton's rear triangle under the bike makes a kickstand unnecessary).

The Btwin Ultra Compact therefore bears comparison with more expensive Bromptons like the C Line Explore we tested in February 2023.

Tern is one of very few other folder makers in this price bracket. The well-regarded Tern Link C8 costs £850 and while its 20-inch wheels mean it doesn't fold as small as the Ultra Compact, they do offer a smoother ride.

Use this box to explain your overall score

Overall, I'm rating the Ultra Compact as Good because much about it is excellent, and it's great value for money, but the handling takes the shine off for me, and it has the lowest weight limit that still meets the requirements of the ISO 4210 standard for bikes.