Bikes Education Fun & Games Science

Although I can’t say I’d care to try, or can in good conscience recommend, that trick where you let go of the handlebars at speed and sit upright in the saddle with your hands at your sides, this video from Ira Flatow’s Science Friday helps explain why it works. [Thanks, Laura!]

26 thoughts on “Why A Speeding Bicycle Tends To Stay Upright

  1. From the video we appear to learn: the reason bikes are stable are not gyroscopic (torque) and not (steering) trail; a model is built that is stable(ish) without those two. That leaves us with …a mystery? (kind’ve of Sopranos ending) Is the answer in the paper? if so, could we have a link to this paper that reveals all?

    1. It should. Google “bicycle rollers” and you’ll find that while training, competitive cyclists routinely balance on bikes that are going nowhere. A treadmill would presumably work the same way, though it would be harder to keep things stabilized – you’d have to regulate your speed very carefully to avoid flying off the front or back of the belt.

  2. I can see 4 wheels that would give gyroscpoic stability to the weird thing in the video.
    4 gyros (2 wheels, plus 2 gryos) are more stable than 2 gyros (2 wheels).
    It is obvious just looking at it.

    Gyroscopic stablisation hasn’t been disproved.

  3. A while back, Make featured a few oddball bikes. One with a hinged seatpost (rear wheel steering) and one with a pair of gears linking the handlebars to the fork. On that one, a left turn on the handlebars made the wheel turn right. If I recall, they said this bike was almost completely un-ridable. Anyway, this paper probably partially explains why. The weight shift would turn the wheel the wrong way! It’s the opposite of stable – even without the rider.

  4. i’m not an engineer or a physics professor, but it would it would seem that there would ALWAYS be a part of a wheel that does the steering and a part that does the trailing, no matter what it was made out of or how minute it is.

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I am descended from 5,000 generations of tool-using primates. Also, I went to college and stuff. I am a long-time contributor to MAKE magazine and makezine.com. My work has also appeared in ReadyMade, c't – Magazin für Computertechnik, and The Wall Street Journal.

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