Video: You can't steer a bike in zero gravity, say researchers

Cornell University experiment shows that while it's gravity that causes you to fall off, you need it to steer

by Simon_MacMichael   March 28, 2014  

Bricycle YouTube still

You can't steer a bike in zero gravity. That's the verdict of researchers at Cornell University after conducting an experiment not in outer space but the more mundane location of a sports hall.

They say that "gravity, superficially the thing that makes it hard to balance a bicycle, is the thing that allows you to steer it."

The team at the School of Mechanical & Aerospace Engineering at the Ivy League institution, located in Ithaca, New York, made what they term a "bricycle" to conduct their research.

It's described as a hybrid between a tricycle and a bicycle, and also has a "zero rest-length spring" which can be adjusted for stiffness.

"Clamping the spring, infinite stiffness, makes a tricycle," say the researchers. "Detaching the spring, zero stiffnes, makes a bicycle.

"At some intermediate value of stiffness, the spring restoring torque cancels the gravity capsizing torque and the bricycle is, for balance purposes, effectively in zero gravity; when not going forwards it is in neutral equilibrium for leaning."

The effect of those adjustments on attempting to steer the bricycle are clearly shown in this video:

Professor Andy Ruina says that while it's gravity that causes cyclists to take the occasional tumble from their bikes, it also proves vital when it comes to steering.

According to the university's website, the findings of the research may prove helpful to designers of mobility aids to assist with rehabilitation from injury, as well as manufacturers of what are termed "narrow-track vehicles," aimed at reducing traffic congestion, such as the Nissan Land Glider shown in this video.

Professor Andy Ruina, who presented the research at the American Physical Socirty's annual meeting in Denver, Colorado earlier this month, said: “What our research shows is that you’ve got to be careful.

“But I’m sure the people designing these things have made this discovery one way or the other,” he added.

11 user comments

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After 3 pints and a pretty decent steak, this is properly genius. Chapeau Road.CC for publishing this on a Friday night!

I was told there would be Cake. Luckily there's http://TestValleyCC.org.uk

KiwiMike's picture

posted by KiwiMike [438 posts]
28th March 2014 - 22:12

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reminds me of this new awesome cargo bike http://vimeo.com/89245058

posted by bigbluebike [16 posts]
28th March 2014 - 22:27

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"Infinite stiffness, makes a tricycle"
Is it infinitely light and infinitely aerodynamic as well? Tricycles are amazing!

posted by Quince [108 posts]
28th March 2014 - 23:33

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In all seriousness, I found the video was really interesting and well explained. And now I want to try out a bricycle.

posted by Quince [108 posts]
28th March 2014 - 23:43

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*Science* du du duh!

Between the S and the LOW

bikeboy76's picture

posted by bikeboy76 [1188 posts]
28th March 2014 - 23:57

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Quince wrote:
"Infinite stiffness, makes a tricycle"
Is it infinitely light and infinitely aerodynamic as well? Tricycles are amazing!

Infinite stiffness also makes a tripod.....Keep thinking Day Dreaming Day Dreaming Devil

Gkam84's picture

posted by Gkam84 [8698 posts]
29th March 2014 - 2:46

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That is some of the worst 'science' I've seen for ages.

It's an application of Newton's Laws of Motion.
To get a bicycle round a corner you basically get it to fall over and then balance it with centrifugal force. Take away the falling over and all you have is the centrifugal force pushing the bike away from the corner. In the same way walking and running are basically falling over and then moving your feet under your body to stop yourself face-planting. It's all about altering equilibrium.

The rig in the film is not a tricycle. It is either a bicycle with stabilisers or it is a quadricycle*. Yep! Just watched again to make sure and I counted four wheels in contact with the ground.

*Quadri- and Quadra- are both acceptable

posted by levermonkey [341 posts]
29th March 2014 - 8:32

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levermonkey wrote:
That is some of the worst 'science' I've seen for ages.

Well, you must be lucky enough to have seen some incredible science because this is top stuff, as reported two long weeks ago at http://cyclingandscience.com/2014/03/16/anti-gravity-cycling/ The work has been presented, in person, to scientists in Japan and the U.S. and none of them have been able to fault it. Wave

posted by cycling science... [5 posts]
29th March 2014 - 18:02

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This from a blog that describes 1 wheel at the front and 3 at the back as a tricycle? 1+3=4.

It is a system out of equilibrium not anti-gravity. You have destabilised the system not removed gravity.

Rider's weight alone not enough to make rig fall over; rider's weight plus centrifugal weight enough to make rig fall over. Newton's Laws of motion and the Laws of Gravity apply. The rig still falls due to gravity all you have done is influenced which way it will fall and the amount of force required to push it over.

IT IS STILL A GRAVITATIONAL SYSTEM!

posted by levermonkey [341 posts]
31st March 2014 - 6:55

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It's steering right to go left, which is why it is initially so difficult to ride a bike. As mentioned, you stop it from falling over by balancing and counter-steer.

Try this at home: ride in a straight line and 'tap' the handlebars to the right; the bike will initially tip and turn left (like in the video).

Difficult to unlearn the behaviour and steer, but it is possible at low speed.

posted by spaceyjase [48 posts]
1st April 2014 - 21:17

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OK, so assuming there was any reason to ride a bicycle in zero gravity wouldn't the fact that the tyres need to maintain contact and friction with a surface be a greater impediment? What about braking?
Riding a bike in space, probably pointless, but I want to try it and I doubt it would end well if I ever got the chance.

posted by drfabulous0 [273 posts]
1st April 2014 - 22:44

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