UK Monster Owners Club Forum » .: Technical :. » Cans, Tyres, Brakes, etc. » Suspension and cornering forces

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Old 26-07-2019, 05:48 PM   #46
utopia
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Gazza ....

Yes, I've done the bicycle wheel experiment many times.
So did all my kids when I explained countersteering to them.

My favourite experiment was approaching a particular, smooth right-hander on my route home from work, while sitting on my left hand.
The right hand was held "open" such that there was enough grip on the throttle to maintain a throttle opening but it was impossible to pull on the right-hand bar .. only pushing was possible (ie turning left).
Flat out on my old TL150 was only 55mph but I used to take that right-hand bend flat out every single evening while being physically unable to steer right directly.

I had done the theory some years earlier but, as Emzedder described, I'd been doing exactly the same thing by feel for years, without needing to do the sums.

Last edited by utopia; 27-07-2019 at 12:24 PM..
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Old 26-07-2019, 05:51 PM   #47
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Originally Posted by Mr Gazza View Post
So a Penny Farthing or uni-cycle cannot turn?
I think I’d include both of those in the ‘Pretty Unrideable’ category!

How do you turn a unicycle? There are no handlebars to counter steer.
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Old 26-07-2019, 05:55 PM   #48
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And the forks aren’t vertical on a penny farthing:

http://www.standardhighwheels.se/?page_id=163
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Old 26-07-2019, 06:06 PM   #49
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Shifting weight can also create a turn...

If you jerk your body weight sideways it causes the steering to turn slightly...
Perhaps unsurprisingly, Mr Foale has considered this element of steering in detail. As before, I can't add anything to his analysis so I will just attach his explanations as they appear in his book "Motorcycle handling and chassis design":







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Old 26-07-2019, 06:12 PM   #50
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Originally Posted by Darkness View Post
I think I’d include both of those in the ‘Pretty Unrideable’ category!

How do you turn a unicycle? There are no handlebars to counter steer.
I would agree with that category!
Uni-cycle might not be a good example in this context, as I think they stop and sort of squiggle them round?

Those Penny Farthings you linked to do have some rake and trail.

I can't really agree nor dis-agree with your contentions

Here are some Tony Foale experiments.





Jeff... Very elegant real world experiment.. TL150 probably not so elegant?
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Old 26-07-2019, 06:17 PM   #51
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.... TL150 probably not so elegant?
Its certainly not so elegant these days.
Its rusting frame actually lies beneath the Leylandii that I'm cutting down.
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Old 26-07-2019, 06:21 PM   #52
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Leylanii sap + heatwave = very sticky Jeff!!!
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Old 26-07-2019, 07:34 PM   #53
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I was reading about these experiments just the other day, Mr Gazza - very ingenious.

For nerds like me, who find this sort of thing interesting, here's a diagram showing what's actually going on with the different arrangements.

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Old 26-07-2019, 07:53 PM   #54
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Caster effect would be interesting for the alternatives.

Do they oscillate at different harmonics?
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Old 26-07-2019, 08:29 PM   #55
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Caster effect would be interesting for the alternatives.

Do they oscillate at different harmonics?
Where the ground trail figure is the same, the self-centring castor effect will be greatest in the 0° castor angle example. This is because it depends on the length of the lever arm (i.e. the line drawn perpendicular to the castor angle across to the centre of the tyre contact patch). The longer the lever arm, the stronger the self-centring.

Over to you, Tony...



Don't know about oscillations though
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Old 06-08-2019, 07:55 AM   #56
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Missed all the above whilst i have been away and need to catch up.
What started it all? need for central baffle in the tank? this may prove me to be wrong (again)
https://www.youtube.com/watch?v=V9pvG_ZSnCc
Hope the video comes out
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