Engines of Our Ingenuity

No. 888:
LEONARDO'S BIKE

by John H. Lienhard

Click here for audio of Episode 888.

Today, we find a bicycle in the wrong place. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

I'm almost used to being surprised by Leonardo Da Vinci; but I was really astonished by an item that turned up in the Codex Atlanticus. That's a collection of Leonardo's drawings that someone pasted into a scrapbook soon after he died.

Leonardo was fastidious about writing on both sides of his paper. The man who made this scrapbook cut a big square hole in each mounting sheet so you could see both sides. Leonardo's students had practiced on the back of some pages. No holes for them. The student scribbles were permanently sealed off.

The scrapbook was dismantled during the 1970s. We could finally see everything. Then the most astonishing thing turned up. In 1504 Leonardo made sketches on two of the pages while he was trying to improve coastal defenses. Nothing special there.

On the back, student sketches: two pornographic drawings and a mocking sketch of Leonardo's favorite model -- a teenage boy, also a student. Still nothing special. But there's one more item in the upper right corner that you or I might hardly notice. It's too familiar. It's a bike -- like the one you rode as a kid.

It has two wheels of equal size -- with spokes. It has pedals, a chain, and a sprocket. It has handlebars.

Leonardo anticipated many things -- helicopters, parachutes, tanks. Most were out of proportion. They would never really have worked. This was different. This one would've worked.

The development of the modern bicycle began in 1816. It took its modern form -- the form in Leonardo's sketch -- around 1885. Very little has changed since then. That odd sketch was pasted into a scrapbook 300 years before the first 19th-century bike. It was unpasted 90 years after such bikes were finished.

The sketch clearly had no connection with the invention of the modern bike. Yet there it sits, quite impossible, but there.

Who cooked up this machine? Leonardo or the student? From what kind of thin air did it flow? Leonardo gives a detail of that sprocket and chain in another codex. We can be almost certain that the student copied the bike from some lost Leonardo drawing.

You see, the bicycle was very hard to invent. The concept of unstable two-wheeled motion didn't come easily. This sketch hints that there might be one optimal bicycle design, and that Leonardo thought it up. It seems he really did create a design so subtle that it took most of the 19th century to reinvent it -- and that he did it entirely in his head, without ever making the real thing.

That's almost too astonishing to believe. But we have no better explanation for that crazy anachronistic drawing -- suddenly spinning into our world from the wrong, wrong, century.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)


Marinoni, A., The Bicycle. Leonardo the Scientist. (Zammattio, C., Marinoni, A., and Brizio, A.M.) New York: McGraw-Hill Book Co., 1980, pp. 154-165.

For more on bicycles, see Episodes 78 and 1083.


The Engines of Our Ingenuity is Copyright © 1988-1997 by John H. Lienhard.

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