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Lateral weight transfer??????/

Posted by LexusFman 
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Lateral weight transfer??????/
June 23, 2015 12:46AM
So I've realized I've been getting conflicting messages about weight transfer. The drivers seem to say you have to shift the weight of a race car in order to be fast, and from what I've seen of drivers at maximum attack, it holds true. But the engineers seem to think weight transfer reduces grip. What I've gotten from that is longitudinal (Front/Back I mean) weight transfer is where its at and lateral (Left/Right or Inside/Outside) weight transfer hurts overall traction, because the front wheels need significantly more grip on turn in since the rears just kind of drag along and the rear wheels need more grip on exit right? But if that's the case then why don't all race cars just run super stiff swaybars to control lateral roll instead of caring about roll centers, COG, polar moment of inertia, roll couple etc??? Alot of good setup geniuses seem to prefer little to no swaybar stiffness for rally/drifting, especially on loose surfaces where you'd think maximizing the most of the grip is what its all about???



Edited 1 time(s). Last edit at 06/23/2015 12:46AM by LexusFman.
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Robert Culbertson
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Re: Lateral weight transfer??????/
June 23, 2015 09:49AM
I'm just going to address the swaybar issue. You threw out a whole bunch of fancy words and phrases, and if you fully understood them, you would understand the swaybar issue.

So let's talk about how a sway bar works. A sb controls roll and not bump of a vehicle. To do this, it has to be decoupled from any bump influences. This is done by connecting it to the other side of the car and having the SB pivot on the chassis. The increase in roll stiffness comes from the unloading of the inside tire, think about that for a second.
As a car is in a corner, the outside suspension is being compressed, and the inside suspension is extending. Now by connecting a SB, the inside wheel is now also being lifted up slightly, and that load from the spring is being transferred to the outside wheel to extend the suspension.
Swaybars work by reducing the vertical load on the inside tire, and transferring some of that spring force to the outside, causing the suspension to settle less. Reduced tire loads means reduced grip.
Swaybars can be used to tune a suspension setup, or create a sharper/lesser turn-in response.
I'd recommend that you pick up a copy of Engineer to Win and Tune to Win by Carrol Smith if you'd like more information.



Edited 1 time(s). Last edit at 06/23/2015 09:53AM by Robert Culbertson.
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john vanlandingham
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Re: Lateral weight transfer??????/
June 23, 2015 11:28AM
Quote
Robert Culbertson
I'm just going to address the swaybar issue. You threw out a whole bunch of fancy words and phrases, and if you fully understood them, you would understand the swaybar issue.

So let's talk about how a sway bar works. A sb controls roll and not bump of a vehicle. To do this, it has to be decoupled from any bump influences. This is done by connecting it to the other side of the car and having the SB pivot on the chassis. The increase in roll stiffness comes from the unloading of the inside tire, think about that for a second.
As a car is in a corner, the outside suspension is being compressed, and the inside suspension is extending. Now by connecting a SB, the inside wheel is now also being lifted up slightly, and that load from the spring is being transferred to the outside wheel to extend the suspension.
Swaybars work by reducing the vertical load on the inside tire, and transferring some of that spring force to the outside, causing the suspension to settle less. Reduced tire loads means reduced grip.
Swaybars can be used to tune a suspension setup, or create a sharper/lesser turn-in response.
I'd recommend that you pick up a copy of Engineer to Win and Tune to Win by Carrol Smith if you'd like more information.

And I'd suggest both of you go drive more.



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Robert Culbertson
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Re: Lateral weight transfer??????/
June 23, 2015 12:57PM
Quote
john vanlandingham
And I'd suggest both of you go drive more.

I agree. I would love to drive at the limit more often.
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john vanlandingham
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Re: Lateral weight transfer??????/
June 23, 2015 02:20PM
Quote
Robert Culbertson
Quote
john vanlandingham
And I'd suggest both of you go drive more.

I agree. I would love to drive at the limit more often.

Curiosity:
How many rallies have you driven?



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Robert Culbertson
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Re: Lateral weight transfer??????/
June 23, 2015 03:01PM
Are we talking stage rallies, TSD rallies, rally cross "rallies" ? smiling smiley
I've driven zip, zero, nada, not a single stage mile in my entire life. I do spend a decent amount of time on paved racetracks though every year.

But you don't care about that, and that's totally okay.

His question was not about stage rally. It was about vehicle dynamics from a slightly higher level, an area where I have a just a little bit of experience and knowledge.
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john vanlandingham
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Re: Lateral weight transfer??????/
June 23, 2015 04:57PM
Quote
Robert Culbertson
Are we talking stage rallies, TSD rallies, rally cross "rallies" ? smiling smiley
I've driven zip, zero, nada, not a single stage mile in my entire life. I do spend a decent amount of time on paved racetracks though every year.

But you don't care about that, and that's totally okay.

His question was not about stage rally. It was about vehicle dynamics from a slightly higher level, an area where I have a just a little bit of experience and knowledge.

Yeah, gravel rally--STAGE--rally...obviously here speaking of gravel stage rally...everything here is about gravel rally..

You know the kid posting? he wants to do gravel rally..

The question should be assumed to be about one's experience in gravel rally...

Driving, building, planning..Gravel rally...



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Robert Culbertson
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Re: Lateral weight transfer??????/
June 23, 2015 05:04PM
When did the idea of coefficient of friction and vertical loading change so much?
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john vanlandingham
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Re: Lateral weight transfer??????/
June 23, 2015 06:15PM
Quote
Robert Culbertson
When did the idea of coefficient of friction and vertical loading change so much?

When did those with zero experience in a subject pontificating become the norm?

Suggesting what you did to a 18 y.o. kid is useless.
It wastes his time and suggesting he beat-off to some beat-off book takes him farther from his goal: He must get a car of his own.



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Robert Culbertson
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Re: Lateral weight transfer??????/
June 23, 2015 06:23PM
The hunger for knowledge is a terrible thing to have. eye rolling smiley
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john vanlandingham
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Re: Lateral weight transfer??????/
June 23, 2015 07:08PM
Quote
Robert Culbertson
The hunger for knowledge is a terrible thing to have. eye rolling smiley

And speaking of knowlege, ever hear the meme "a man has got to know his limits"?

Hunger for knowledge is one thing--- repeating recently aquired theories to innocent newbs who might mistakenly believe they are reading about "knowledge" is another..

You have a thirst for knowledge? Then read this nice little essay:
http://www.bocc.ubi.pt/pag/peirce-charles-fixation-belief.pdf

It begins:

The Fixation of Belief
(Popular Science Monthly 12 (November 1877), pp. 1-15)
(
tradução em português
)
Charles Sanders Peirce
I
Few persons care to study logic, because
everybody conceives himself to be proficient
enough in the art of reasoning already. But
I observe that this satisfaction is limited to
one’s own ratiocination, and does not extend
to that of other men.
We come to the full possession of our
power of drawing inferences the last of all
our faculties, for it is not so much a natural
gift as a long and difficult art.



John Vanlandingham
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Re: Lateral weight transfer??????/
June 23, 2015 07:36PM
Quote
john vanlandingham
How many rallies have you driven?

Curiosity:
How many rallies have you driven?
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Robert Culbertson
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Re: Lateral weight transfer??????/
June 23, 2015 07:50PM
Quote
john vanlandingham


And speaking of knowlege, ever hear the meme "a man has got to know his limits"?

Hunger for knowledge is one thing--- repeating recently aquired theories to innocent newbs who might mistakenly believe they are reading about "knowledge" is another..

HA! Bwahahahahahahahaha!!!!!! Thanks for the laugh John smiling smiley
John, how do you think a sway bar works?

I see that you have placed me into a box as someone who is "young" and lacks all the experience of the great JVL. While I may be "young" by your standards, I learned most of what I know through my own successes and failure, and through the successes and failures of friends (who happen to work in F1, NASCAR, LeMans prototype teams, and the aerospace and automotive industry... as engineers). All that we have learned is through reading, testing, experiencing, and talking to those with much more experience.


"The man feels that, if he only
holds to his belief without wavering, it will
be entirely satisfactory. Nor can it be denied
that a steady and immovable faith yields
great peace of mind. It may, indeed, give
rise to inconveniences, as if a man should resolutely
continue to believe that fire would
not burn him, or that he would be eternally
damned if he received his ingesta otherwise
than through a stomach-pump. But then the
man who adopts this method will not allow
that its inconveniences are greater than its
advantages. He will say, “I hold steadfastly
to the truth, and the truth is always wholesome.”
And in many cases it may very well
be that the pleasure he derives from his calm
faith overbalances any inconveniences resulting
from its deceptive character"

This bit was pretty darn good.



Edited 1 time(s). Last edit at 06/23/2015 07:52PM by Robert Culbertson.
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john vanlandingham
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Re: Lateral weight transfer??????/
June 23, 2015 10:54PM
I haven't put you in any box, your own admitted enjoyment of making things much more complicated than need be and excessive pontification of theory to the wrong people in the wrong context has put you not in a box but in a "territory'..



John Vanlandingham
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Robert Culbertson
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Re: Lateral weight transfer??????/
June 24, 2015 10:27AM
Quote
john vanlandingham
I haven't put you in any box, your own admitted enjoyment of making things much more complicated than need be and excessive pontification of theory to the wrong people in the wrong context has put you not in a box but in a "territory'..

Well at least I have some land to call my own.
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