Bicycles

One-of-a-kind folding bike may be the lightest ever

One-of-a-kind folding bike may...
Sorry, but there are no plans for commercial production
Sorry, but there are no plans for commercial production
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The three-stage folding process reportedly takes just a few seconds, requiring the flicking of three quick-release levers
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The three-stage folding process reportedly takes just a few seconds, requiring the flicking of three quick-release levers
Titanium is used in the bottom bracket, chain, spokes, pedals, suspension spring, and "every nut, bolt and washer"
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Titanium is used in the bottom bracket, chain, spokes, pedals, suspension spring, and "every nut, bolt and washer"
A closer look at the rear triangle
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A closer look at the rear triangle
Derek Cranage's bike, all folded up
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Derek Cranage's bike, all folded up
Sorry, but there are no plans for commercial production
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Sorry, but there are no plans for commercial production
View gallery - 5 images

Given that they have to incorporate hinges, latches and other structural considerations, compact-folding bikes generally tend to be heavier than their regular counterparts. Nonetheless, a British designer has managed to build one that tips the scales at just 6 kg (13.2 lb).

Just for reference, excluding models with ridiculously small wheels, the lightest folding bikes that we've previously covered include the 6.7-kg (14.8-lb) Hummingbird and the 8.5-kg (18.75-lb) Ultra X.

This latest 16-inch-wheeled bike – which is a one-off – was created by Derek Cranage, who previously gained attention by converting an existing Brompton folding bike into an ebike that weighed less than 10 kg (22 lb).

His latest creation incorporates a frame that was designed and built entirely from scratch, with the whole bike folding down into a package measuring 590 x 600 x 260 mm (23.2 x 23.6 x 10.2 in). The three-stage folding process reportedly takes just a few seconds, requiring the flicking of three quick-release levers – no wing nuts or other fasteners are involved.

Derek Cranage's bike, all folded up
Derek Cranage's bike, all folded up

The main frame and the coil-spring-suspended rear triangle are made of a mix of carbon fiber, titanium and 7020 aircraft aluminum tubing, the latter being precisely milled so that it's thicker and stronger at the joints (with a wall thickness of 2.5 mm) and thinner and lighter in the middle of each tube (1.5-mm wall thickness).

The saddle, seatpost, forks and handlebars are all made of carbon fiber. Titanium is used in the bottom bracket, chain, spokes, pedals, suspension spring, and "every nut, bolt and washer." In short, Cranage tells us that each item has been lightened to its strength limit, up to a tolerance of a tenth of a gram.

A closer look at the rear triangle
A closer look at the rear triangle

And yes, he says that the bike does in fact ride incredibly well. Given that he has no plans to manufacture it commercially, though, why did he bother?

"Two years ago I developed cancer (I am 78 years old) and while having my intensive treatment, I wanted something to keep me occupied, so I started designing a Brompton-beating bike," he tells us. "When I finished the design I was still on treatment, so I started to build it."

And should you be wondering, Cranage says that his condition has since improved.

View gallery - 5 images
7 comments
Dilettante
You must surely be aware of the Moulton bicycle http://www.moultonbicycles.co.uk to which this design bears some resemblance. My 1982 Moulton AM weighs in at 10kg but Moulton have lighter models in their range. All have full suspension.
Daveb
I love this magazine so much with its top writers like Ben, frequent updates, and so many interesting topics. Thanks so much, New Atlas!
PassingBy2
Finally, a tiny-folder folder as small as my (all Al) Bickertons, and lighter still.
Hmm. Bet it costs me more that the AUD200 ea I paid for mine :)
But nice try. Nice work. Well done that man.
LinBrand
Looks like my Bike Friday pakiT and a Brommie had a baby, lol. Btw, you can get a Bike Friday pakit as light as 15lbs if you're willing to fork over the $$. Mine is just under 19 lbs (best balance of price and weight for me). This thing looks a lot like the pakiT from Bike Friday, as well. Kind of a rip off.
Noel Rayos
I have a commercially available Fnhon Freedom with a single-speed belt drive that I've gotten down to 5.5Kg with Ace Titanium-spindle pedals, a carbon crank, saddle, seatpost and fork. I also swapped over to a Litepro ultimate brakeset. This is without going all-titanium with the bolts.
wle atlanta
why does it have that chain tensioner if no r derailleur?

how wobbly is it, at what rider weight

does it have gears?

i do like it but it needs gears...
Derek cranage
Other comments - The Fnhon Freedom When folded is over twice the volume of my bike it does not fold very small and has smallEr wheels and does not ride good.
My rides as good as any full size bike. Adding gears adds 1.2 kg. The chain tensioner is required when the rear triangle is folded under. Moulton, bicketon and pakiT all are heavier and none fold anything like as small. The only bike that folds just slightly smaller is the brompton which their lightweight one is massively heavier.