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Investors sought for development of “first double drive bike”

A Dutch surgeon has come up with an unusual solution to the problem of getting more power into a bike: a drive system that combines a conventional pedals and chain drive with a toothed belt powered by hand cranks.

The idea of the 4 Strike Bike is to bring more of the body’s muscles into play. “On a regular bike about 50 muscles are in active use whereas the 4 Strike Bike requires the active use of 128 muscles, i.e. an increase of muscle power of more than 150%,” according to the manufacturer.

To achieve this, the 4 Strike Bike has a patented pedalling mechanism incorporated into the handlebars that enables upper body ‘pedalling’ and steering to be combined. A stabiliser takes care of any potentially problematic steering inputs.

A toothed belt takes power from the hand cranks to the main drive. The hand cranks can be locked so that the bike behaves as a normal bike when the rider is getting on and off.

The 4 Strike Bike is the brainchild of retired surgeon Lex van Stekelenburg, who says: “I developed troublesome back and shoulder complaints from years of performing lengthy surgical operations while standing with a bent and crooked posture. To recover from and prevent these problems, I came up with the idea of this bike. I then designed and built the first bike and began to use the 4 Strike Bike successfully.”

Van Stekelenburg’s key claims for the 4 Strike Bike are that it will be faster than a regular bike and provide more balanced exercise because it uses the body’s upper body as well as the legs.

“The 4 Strike Bike makes active use of more different muscles and the use of arm and torso muscles aids breathing, leading to better aeration of the tops of the lungs. The heart has a more balanced workload, now supplying blood to muscles in both upper and lower body,” the company claims.

“The 4 Strike Bike gives you a total body workout, generates upper body warmth, aids ventilation, and leads to total body fitness.

“This modern bicycle is a faster way of transport on the road, and the bike can be adjusted to suit different traffic situations and personal preferences.”

Hand-cranked bikes

The maker acknowledges that adding hand cranks to a bike is not a new idea, but claims the 4 Strike’s approach is unique.

“There have been several strangely powered bikes on the market involving separate use of the arms by the rider while seated upright but not resulting in a harmonious cycling motion,” they say. “There are bicycles with a drive on the front wheel, whereby a non-synchronous, non-parallel, unnatural movement of the arms and legs occurs.

“Other designs have the handlebars at chest height with the rider seated upright. Here the rider pulls on the handlebars without the use of the weight of the upper body and without synchrony between shoulders, torso and hips, with low back pain as a result.”

The 4 Strike is different because the design and position of the hand cranks allows the rider to bring gravity into play. “The weight of the upper body is shifted alternately from the left handle to the right handle and back. The gravitational force of the upper body weight brings the handles and the crank into motion.”

The mechanism is undoubtedly clever, but it’s hard to see how it will be substantially better or faster than a conventional bike.

The folks at Cyclorama.net have this to say on hand-cranked bikes: “The amount of energy we can draw on to propel our bicycles is limited not by how much muscle we can bring to bear but by the amount of fuel we can burn which is in turn restricted by the amount of oxygen we can process. Bigger lungs and/or better lung function will allow us to go faster but extra pedals for our front limbs will just add unnecessary weight and actually slow us down.

“This idea gets rolled out every twenty years or so as each new generation of inventive geniuses discovers bikes and decides to improve them. Bicycles so equipped didn't go any faster a hundred years ago. They still don't.”

You can read all about the 4 Strike Bike on its website. Lex van Stekelenburg is seeking investors to develop the idea, and can be contacted through his ‘Participate’ page.

Our official grumpy Northerner, John has been riding bikes for over 30 years since discovering as an uncoordinated teen that a sport could be fun if it didn't require you to catch a ball or get in the way of a hulking prop forward.

Road touring was followed by mountain biking and a career racing in the mud that was as brief as it was unsuccessful.

Somewhere along the line came the discovery that he could string a few words together, followed by the even more remarkable discovery that people were mug enough to pay for this rather than expecting him to do an honest day's work. He's pretty certain he's worked for even more bike publications than Mat Brett.

The inevitable 30-something MAMIL transition saw him shift to skinny tyres and these days he lives in Cambridge where the lack of hills is more than made up for by the headwinds.

9 comments

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lookmanohands [119 posts] 2 years ago
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 39 31

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Yorkshie Whippet [526 posts] 2 years ago
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Err, how do you steer?

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kitkat [348 posts] 2 years ago
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I would have thought this was perfectly applicable with recumbent bikes. Uprights are a bit more suspect!  39

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The Rumpo Kid [589 posts] 2 years ago
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Where's Mr. Garrison when we need him?

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j1mmy76 [66 posts] 2 years ago
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Can't see any problem with having your fingers up near a moving belt  23

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TeamCC [146 posts] 2 years ago
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Would also work great as a stationary bicycle in the gym Capital Cycles

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Gkam84 [9086 posts] 2 years ago
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It works perfect in recumbents, but I wouldn't like to see that in action. You are going to be on the ground more than upright

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6654henry [56 posts] 2 years ago
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The body is an engine - doesn't matter how many driveshafts you attach you can still only get the same performance. The blood is carrying the oxygen but now it has to get to loads more muscles....... The guys at Cyclorama.net are right.

If it were a sprint you'd produce more power i think.

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bonni [1 post] 2 years ago
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if you use arm and leg cranks you can get 31% more max.power output than a normal bike at the same heart rate! you also have a better endurance performance. This is the result of a study of the New Mexico state university
see http://www.ihpva.org/HParchive/PDF/21-v6n3-1987.pdf the study is shown on the pages 8+9+18

There is another arm and leg crank bike www.varibike.com
The varibike is already on the market