【Folding Bike】Dahon K One 20" Dual-Chainwheel Folding Bike: Not just an upgrade, but a leap forward! Exceptional value for money, why is it even lighter?

Last updated: 9 October 2026

The Dahon K One double chainring (model FDA083) is a 20-inch aluminium folding bike with 451 wheels, a 53/39T double chainset giving 18 speeds, and disc brakes. The official site lists 11.95 kg and does not say whether pedals are included; the video scale also showed 11.95 kg. Compared with the 9-speed single-chainring K One (FKA091), it adds a second chainring and bigger 451 rims yet is officially slightly lighter, which suits riders who want a folder for longer, faster rides.

This English version summarises our July 2023 Cantonese video. Jason said this version was "more than a simple upgrade": so much had changed that it felt like skipping a grade.

Single or double: what is the difference?

Both are 20-inch aluminium folders with disc brakes. The double FDA083 pairs 53/39T chainrings with a 9-speed cassette (11-28T on the 2023 batch in our video) and rolls on 451 rims. The single FKA091 has 9 speeds, weighs about 12.08 kg and folds to 87 × 67 × 41 cm (official site). The older single-chainring bike in our video had an 11-32T cassette on 406 rims (see also our earlier K One article); we have not yet confirmed it is the same bike as the current FKA091, and The official site does not list either figure. the official site notes that the latest FDA083 batch uses Shimano Sora 18-speed shifters and derailleurs, unlike the bike in our video, so ask us about the current spec.

What else changed on the double?

The square-taper bottom bracket became a hollow one, which the video says is smoother and lighter. Jason said the 53/39T chainset makes climbs easier. The 451 wheels come with a longer, redesigned fork that leaves room for upgrades, plus narrower road tyres for less rolling resistance. In our separate big wheel vs small wheel roll test, a 20-inch 451 Tern Verge D9 rolled 484 m against about 400 m for 16-inch folders (a different bike, so only a rough guide). The catch: you must buy 451 tyres, as 406 tyres will not fit.

Smaller changes include a cable brace on the frame, folding pedals (Wellgo, per the official site), a slimmer sporty saddle, a Dahon badge on the stem, and a new front mounting hole for a rack or basket. Jason said that mounting hole was the change he liked most. The ergonomic grips, gear indicator, adjustable bar and saddle height, 140 mm disc brakes front and rear, and kickstand all carry over.

How much does it weigh, and how small does it fold?

Despite the bigger wheels and extra chainring, it weighed less: 11.95 kg on our scale against about 12.2 kg for the older single-chainring K One in the video, the same figure The official site lists (it does not say whether pedals are included). Jason put this down to the hollow bottom bracket and the road wheels. The official site does not publish a folded size for the FDA083; our video shows 86 × 42 × 69 cm, similar to the FKA091 and larger than a 16-inch folder.

Is the K One double any good, and which should I buy?

If you already ride a fair bit and want a folder for long cycle-track rides and speed on the flat, the double's 18 speeds and 451 wheels give you more gearing. For short trips and simpler shifting, the 9-speed FKA091 is enough. Both weigh about 12 kg; if you carry the bike onto the MTR or up stairs every day, the 16-inch Dahon K3 Plus 2nd gen (9.8 kg, per Dahon via our product page) is far easier.

The K One double FDA083 You will be working two shifters, and riders who only commute short distances may not need 18 speeds. The K One single FKA091 has fewer gears to choose from. Message us on WhatsApp or call 2342 0780 to check the current spec before you buy.

FAQ

How much does the Dahon K One weigh?

The official site lists the double FDA083 at 11.95 kg without saying whether pedals are included, and the single FKA091 at about 12.08 kg. The video scale also showed 11.95 kg for the double.

Does the K One use 406 or 451 wheels?

The double FDA083 uses 20-inch 451 wheels; the older single-chainring K One in our videos uses 406. The rims differ in diameter, so tyres are not interchangeable.

Which shop listing is the double chainring version?

"Dahon K One Super Light 20inch 451 18speed Folding Bike FDA083" is the double; the frame in our video is also labelled FDA083. "Dahon K One 20inch Folding Bike FKA091" is the 9-speed single.

Further reading

• Big wheels vs small wheels: how far 9 bikes roll
• Dahon K3 Plus 2nd gen vs Mini 349
• Dahon folding bikes at Jollymap

Update log: 9 October 2026. Added the shop model numbers (double FDA083, single FKA091), a comparison chart, official-site weights and the note on the latest Shimano Sora batch, an FAQ and quotes from Jason; replaced short links with full URLs and rewrote this English version.

Sources

• Dahon official site

Visit the shop

If you would like to see a bike in person, come to the Jollymap store in Kwun Tong: Room H, 4/F, Hoi Yuen Industrial Building, 47 Hoi Yuen Road. Telephone 2342 0780. Monday to Friday 12:00–20:00; Saturday, Sunday and public holidays 11:00–19:00.

Store address, map and opening hours

Colours and stock change. To check what is available now, message us on WhatsApp or call 2342 0780.