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Old 05-10-2007, 07:23 AM   #1
acecycleins
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Default Re: Motorcycle Cornering Physics

I don't have you answer but I know who does: Keith Code- The same guy that runs training schools in California. He wrote a piece about the subject that what printed in one of the regular print media rags that we all read. Someone here should remember which publication. He had very interesting explainations to why we lean and most of them have very little to do with the actual mechanics of turning itself.
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Old 05-10-2007, 07:24 AM   #2
teapotdome
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Default Re: Motorcycle Cornering Physics

Best source to check out is David Hough's book, "Proficient Motorcycling."



Like Prego, It's in there!



First!
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Old 05-10-2007, 07:27 AM   #3
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Default Re: Motorcycle Cornering Physics

Leaning doesn't cause turning. Turning causes leaning.



Even people running in track events lean as they go around corners. The slower they go, the less they lean. When a moving mass (the runner or the bike or the whatever) changes direction, it is accelerating. the forces between the object and the thing it's pressing against to move (the ground) have to be balanced, or the object will tip over.



Banked tracks (and roads, for that matter) are pre-leaned so that the forces between the (car/bike/runner) are prependicular to the surafce of the track durning turns.



If your son likes physics, do a google search for

"vector force diagrams". You can use that as an excuse to teach him algebra,trigonometry, and calculus as he's learning physics.



If he doesn't follow all that, just tell him he'll find out the answer when he's older.



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Old 05-10-2007, 07:31 AM   #4
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Default Re: Motorcycle Cornering Physics

snooze ya lose bub
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Old 05-10-2007, 07:33 AM   #5
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Default Re: Motorcycle Cornering Physics

"cause I said so" usually works with my kids, or else I ask them if they got the laundry folded yet and they skedaddle pretty quick
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Old 05-10-2007, 07:43 AM   #6
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Default Re: Motorcycle Cornering Physics

Or you could try this: www.tonyfoale.com



Read the "Balancing Act" article; there's a section about cornering.



The gist is that leaning overcomes the gyroscopic precession of the spinning wheel and gets the wheel pointed into the turn. Simply turning the wheel in the desired direction cannot overcome this force above a fairly low speed.



Of course, in order to get the bike to lean in the proper direction, we have to deflect the front wheel in the opposite direction of the desired turn (countersteering), but this "backward" defection is only momentary. One the bike is leaned over, the front wheel points in the direction of the turn.



Uh, yeah, I think that's it.
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Old 05-10-2007, 07:49 AM   #7
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Default Re: Motorcycle Cornering Physics

Explaining a pretty complex phenomenon simply is a big challenge.



I have struggled with this myself, and the simplest explanation I can accept is to think of counter-steering as "falling into a turn".



Motorcycles (and bicycles) are not stable at rest. Anyone who has fallen over on either knows this. Motorcycles are stable at speed due to the gyroscopic effects of the spinning tires.



In order to go around a turn you need to "fall" into it. You temporarily upset the balance of the bike by pushing one of the handlebars forward. The bike "falls" a small amount in this direction, all the while you are still going forward. You can turn the bike upright again by straightening the handlebars.



The only reason you don't take a dirt nap is because the gyroscopic effect of the spinning wheels is still greater than the upsetting "falling" force you put on the handlebars.



The gyroscopic effects also help explain why at low speed you don't need to counter-steer.



Take a wheel off of a bicycle. Preferably off of a bicycle you own, cause someone will need it back. I will catch up to the bastard who stole my front wheel back in the fifth grade. It is only a matter of time.



OK, do the classic physics experiment where your young-in holds out the spinning tire by the hub, and then attempts to "steer" it. That gyroscopic effect is strong, isn't it?



Or you could just have him go ask his mother this question while you go riding.



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Old 05-10-2007, 08:00 AM   #8
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Default Re: Motorcycle Cornering Physics

Sorry. Asleep at the bars again. You can't obviously bring the bike upright again merely by straightening the handlebars.



I need coffee. Or a large jar of pharmaceutical grade caffeine and a SPOON.
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Old 05-10-2007, 08:15 AM   #9
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Default Re: Motorcycle Cornering Physics

I suspected it has to do with vectors...that the change of angle in the bike causes a new vector in the form of a turn. I didn't do too well in High School Physics, and I damn sure didn't mess with it in college!
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Old 05-10-2007, 08:20 AM   #10
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Default Re: Motorcycle Cornering Physics

I knew there was an upside to having kids. Brute force, minor tortures, and slavery! Things I would never do to my dogs because they would never understand I was just doing it for fun.
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