Highlights from the 2014 LA Auto Show

Bygen's Hank Direct Bike swaps a chain for direct-drive levers

By

August 27, 2014

The Hank Direct Bike offers an alternative to traditional folding bikes ... and to chains ...

The Hank Direct Bike offers an alternative to traditional folding bikes ... and to chains or belt drives

Image Gallery (6 images)

Folding bicycles definitely have an advantage when it comes to easy toting and storage, although their chain presents a design challenge – it can’t just be folded sideways along with the frame, and there’s a risk that it will transfer gunk onto the rider’s clothing as they’re carrying the bike. Korean manufacturer Bygen has devised a solution, in the form of its Hank Direct Bike. Instead of a chain or belt drive, it has levers that transfer power from the pedals to the rear wheel.

The levers are joined to the hub via an articulated linkage. This allows them to extend forward, placing the pedals in the "normal" position beneath the saddle. On some other direct-drive bikes (such as penny farthings), the pedals/cranks are located right on the wheel.

Just because it’s a direct-drive, however, doesn’t mean that the Hank is a fixie. It actually has three available gear ratios, thanks to a hub transmission. Additionally, according to Bygen, the elimination of variations in chain tension results in a 7 to 8 percent increase in pedaling power.

The rear end slides forward, along the rail-like front section

As you might have already noticed, the Hank’s frame doesn’t actually fold. Instead, the rear end slides forward, along the rail-like front section. This arrangement allows the bike to be tipped back and stored in a vertical "standing" position, plus it lets smaller riders set the cockpit length to their liking, then lock it in place.

The handlebars can also be folded back, for easier carrying and storage.

Thanks to the use of carbon fiber in its frame and 20-inch wheels, along with its unique design, the Hank reportedly weighs in at just 7 kg (15 lb). It’s being presented to the public at this week’s Eurobike show in Germany, although there is presently no word on pricing or availability.

You can see a demonstration of its direct-drive system in the video below.

Source: Bygen via Bike Radar

UPDATE (Sept. 10/14): A Bygen representative has told us that the Hank will go on sale in Korea as of this October, with overseas distribution to follow sometime after. It will start out priced at US$5,000, although the company is hoping to be able to lower that price as distribution widens.

About the Author
Ben Coxworth An experienced freelance writer, videographer and television producer, Ben's interest in all forms of innovation is particularly fanatical when it comes to human-powered transportation, film-making gear, environmentally-friendly technologies and anything that's designed to go underwater. He lives in Edmonton, Alberta, where he spends a lot of time going over the handlebars of his mountain bike, hanging out in off-leash parks, and wishing the Pacific Ocean wasn't so far away.   All articles by Ben Coxworth
10 Comments

> Folding bicycles definitely have an advantage when it comes to easy toting and storage, although their chain presents a design challenge – it can’t just be folded sideways along with the frame, and there’s a risk that it will transfer gunk onto the rider’s clothing as they’re carrying the bike.

Incidently, why isn't there any folding bike with a belt drive?

Because it can't fold?

I have one on my standard bike, and love it: Silent, clean, zero maintenance.

Freyr Gunnar
27th August, 2014 @ 03:02 pm PDT

Nice bike design here.

But Freyr is a belt more efficient than a conventional chain drive? According to Jason Smith at Friction Facts, the answer is no. By his measurements, a conventional chain drive consumes 2.92 watts on average, while the belt eats up 3.93 watts. Here's the whole article. http://www.cyclingnews.com/features/chain-drive-or-belt-drive-whos-faster

The Hoff
27th August, 2014 @ 03:53 pm PDT

Does this thing have gear, because if not that's a major tick against it.

MattII
27th August, 2014 @ 05:19 pm PDT

7% more efficient? Perhaps but why does it look as though the person in the demo has such an uneven pedaling motion? Amazing amount of technology has gone into this, nice work ......... if it works!

Rehab
27th August, 2014 @ 05:46 pm PDT

Wow! ...I really hope this actually works/comes on the general market: does somehow look a little too good to be true.

Also, they may well have to change their logo if they don't want BMW to sue them into the ground before they even get started.

tapasmonkey
27th August, 2014 @ 11:45 pm PDT

A chain has no problem with a sliding, rather than folding design, so that fails as a rationale. As for the efficiency comparison, they are either lying or using a rusty chain on a broken bike to get their chain numbers, and ignoring the flex and friction in their own system. The awkwardness in the video probably comes from a very wide pedal placement. Carbon fiber can't save this turkey. That english translation in the video shows the quality standard at Bygen - only the accent is right on.

Bob Stuart
28th August, 2014 @ 06:15 am PDT

Interesting concept. However, I would suspect that you would get a significant amount of flex in the "crank arms" as they are extremely long when in the forward position. I think this would result in a very mushy feel if you were peddling pretty hard. It also looks like your feet are spread quite a bit farther apart - which could put undue stress on your knees if used for extended rides.

Michael Logue
28th August, 2014 @ 09:03 am PDT

The model weighs maybe 89 pounds? I weigh 225 and I could tear that drive system apart in 10 pumps (or less). This product is a liability that BMW will certainly try to distance itself from.

Paulinator
28th August, 2014 @ 09:55 am PDT

An innovative idea.

But Bob Stewart's comments are right to the point; If it slides, why not a sliding chain system? Looks like another solution looking for a problem.

Edgar Castelo
28th August, 2014 @ 12:06 pm PDT

It looks like an old locomotive engine.

@Freyr Gunnar

There are many folding bikes with belt drive. Dahon, Bike Friday, Tern ...

Guy Lamoureux
3rd September, 2014 @ 03:43 pm PDT
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