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Old 31st July 2003, 07:51 PM   #141 (permalink)
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Talking

Two then
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Old 31st July 2003, 07:53 PM   #142 (permalink)
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Quote:
Originally posted by logiclee
Not wanting to start a slanging match but I suppose it boils down to who do you think has got it right.

The guy who's a circuit instructor, car tester to some of the top name companies, world record holder, works as part of the World Rally Championship, mixes with top chassis designers and has a website dedicated to driving dynamics as well as Scoobynet.

Or

The guy who's read a book.

I am sorry, but you suppose wrongly.

You do not display logic at all by making the above statement: you are not invalidating the argument here, but discrediting the person who put the argument forward. Logically, this is invalid.

It's like saying the majority is always right. The majority isnt always right.
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Old 31st July 2003, 08:08 PM   #143 (permalink)
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Let's see if we can summarise the standpoints of the 2 sides to this debate...

Simon says...
That there is only advantage in less weight bearing on the contact patch of any tyre, weight of any kind is self defeating to some extent from 1kg onwards, there is no advantage in grip from added weight, there is 'for twice the weight always less than twice the grip'

I say...
There is an optimum figure for the ground pressure of any tyre, the ground pressure being applied either thru mass or apparent weight.

We have all seen graphs that show 'something'.

http://www.neohio-scca.org/clubinfo/...educed%202.pdf

Simon says...
These [graphs] clearly show that grip is lessening all the time compared with weight bearing on the tyre.

I say...
These [graphs] show that after just a couple of kgs the tyre gains 1.4/1.5 times the bearing load on the 'grip' account.
To my eyes the graphs show that upto a certain point this remains the case, however at a point where the tyre reaches its optimum bearing/grip level the curve falls off in a manner similar to that Simon claims happens at 1kg...
I cannot see on any graph [all presented by Simon] that shows any 'debit' on the graphs HE has presented.

Simon says...
The set of graphs from NEOHIO show that the line is below 45degrees and therefore by my own admission there is a los along its length. QED he is right!

I say...
The '45 degree' thing assumes equal scale rates along x-y axes, so although the line is indeed below 45degrees, the equal line in these graphs would be at a lesser angle due to un-equal x-y axis scales.

---------------
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Old 31st July 2003, 08:13 PM   #144 (permalink)
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I would have thought it was obvious that in practical applications that a higher weight hinders grip.
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Old 31st July 2003, 08:15 PM   #145 (permalink)
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Claudius

Not saying who is right because I don't know.

You have your own opinion on who you think is right and I have mine. No problem.

Let me ask you this, if you had electrical problems in your house would you take he advice of a qualified electrician or someone who had read a couple of "DIY electrics" books?

Logic itself would dictate that you would trust someone who has expertise and experience in that particular field.
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Old 31st July 2003, 08:19 PM   #146 (permalink)
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Quote:
Originally posted by paul
I would have thought it was obvious that in practical applications that a higher weight hinders grip.
But the 'question' is does that apply from 1kg on or does the disadvantage only appear after we have exceeded the grip properties of the rubber?

Is weight always bad?
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Old 31st July 2003, 08:22 PM   #147 (permalink)
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Quote:
Originally posted by logiclee


Logic itself would dictate that you would trust someone who has expertise and experience in that particular field.
Well Mr. Spock,

Hoover or Mr Dyson... errr
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Old 31st July 2003, 08:27 PM   #148 (permalink)
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Sorry if I may have missed this question..

Is the relationship between the cornering forces and weight linear?

Or to put it another way.

Does a 2000kg car have twice the energy of a 1000kg when taking the same corner at 60mph? What about at 120mph

I would have thought the higher the speed the worse the weight is going to effect you. Am I right in thinking this? It seems to be the case when braking.

Lee
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Old 31st July 2003, 08:29 PM   #149 (permalink)
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Mycroft, this is where I am confused, you said earlier when replying to Simons third comment.

"3/. 'It is unquestionable that doubling the load on a tyre less than doubles the grip it produces (we've all agreed this above).'

WRONG, I question this and I am yet to be orovided with any proof of such."


To me Simons comments on this area made sense and I have no idea where you were going with that arguement.


But then you've just said.

"These [graphs] show that after just a couple of kgs the tyre gains 1.4/1.5 times the bearing load on the 'grip' account."

1.4/1.5 is not double, so therefore Simons point was correct after all?
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Old 31st July 2003, 08:37 PM   #150 (permalink)
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Well Mr. Spock,

Hoover or Mr Dyson... errr
I think you will find that Mr Dyson was a very well respected and experienced engineer in the field of Cyclone suction. He had a very good marketing idea.

He wasn't a Joe Bloggs who picked the info up from the Library.

But please no more slanging or it will spoil this thread.
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Old 31st July 2003, 08:37 PM   #151 (permalink)
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Quote:
Originally posted by logiclee
Sorry if I may have missed this question..

Is the relationship between the cornering forces and weight linear?

Or to put it another way.

Does a 2000kg car have twice the energy of a 1000kg when taking the same corner at 60mph? What about at 120mph

I would have thought the higher the speed the worse the weight is going to effect you. Am I right in thinking this? It seems to be the case when braking.

Lee
It is amazing that despite not keeping up with the thread or even having any idea of the opposing views or the state of play that you feel able to place your faith so readily in one camp... you sir are obviously a genius!!!
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Old 31st July 2003, 08:38 PM   #152 (permalink)
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Quote:
Originally posted by logiclee
Claudius

Not saying who is right because I don't know.
Same here


Quote:
Originally posted by logiclee
You have your own opinion on who you think is right and I have mine.
Actually, I dont think they are really saying different things

I dont doubt Simon knows his stuff.

What I would really like is to see Damian Harty clear up the misunderstandings and make this thread valuable for ignorant people like me who are simply enthusiasts and know little about the actual physics involved.


Quote:
Originally posted by logiclee
Logic itself would dictate that you would trust someone who has expertise and experience in that particular field.
Logic would not dictate that. Experience or common sense would.

Let's not talk about this crap, call it whatever you like. Let's see what I need to do to get around corners faster
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Old 31st July 2003, 08:42 PM   #153 (permalink)
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you sir are obviously a genius!!!
I like to think so but not in this field.

I'm asking a genuine question to which I don't believe has been answered in the other posts.

If you feel its beneath you to answer then perhaps Simon can later.

Cheers
Lee
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Old 31st July 2003, 08:45 PM   #154 (permalink)
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Quote:
Originally posted by Thorin
Mycroft, this is where I am confused, you said earlier when replying to Simons third comment.

"3/. 'It is unquestionable that doubling the load on a tyre less than doubles the grip it produces (we've all agreed this above).'

WRONG, I question this and I am yet to be orovided with any proof of such."


To me Simons comments on this area made sense and I have no idea where you were going with that arguement.


But then you've just said.

"These [graphs] show that after just a couple of kgs the tyre gains 1.4/1.5 times the bearing load on the 'grip' account."

1.4/1.5 is not double, so therefore Simons point was correct after all?
Ahh, I see where you are confused OK,

200lb downforce gives 280lbs of sideways resistance on those graphs [roughly]...

At 400lbs there is 560lbs the ratio of the difference remains the same, however with every doubling on the downforce [200-->400] there is doubling of the grip [280--->560]

Can you see that? As one doubles so does the other, the ratio of adherence remains at 1.4 / 1.5 but the grip doubles as the weight doubles.

These graphs were presented as proving that the grip lessens immediately from 1kg... they do not do this they clearly show what I have said all along, 'only after the tyre reaches its optimum adherence/weight limit will the tyre start to show diminishing returns for the weight applied.
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Old 31st July 2003, 08:48 PM   #155 (permalink)
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Quote:
Originally posted by Mycroft
But the 'question' is does that apply from 1kg on or does the disadvantage only appear after we have exceeded the grip properties of the rubber?

Is weight always bad?
the grip limits will be reached quicker in a heavier car. so this all getting pointless arguing theory. theory doesnt matter when the car is mid corner just about to break away.
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Old 31st July 2003, 08:55 PM   #156 (permalink)
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Quote:
Originally posted by paul
the grip limits will be reached quicker in a heavier car. so this all getting pointless arguing theory. theory doesnt matter when the car is mid corner just about to break away.
That is not the debate, the debate if you want to join in is about the point you have avoided, the real value of this debate is that through its' resolution that 'brown-trouser moment' may just be avoided.
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Old 31st July 2003, 08:57 PM   #157 (permalink)
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Quote:
Originally posted by Mycroft
That is not the debate, the debate if you want to join in is about the point you have avoided, the real value of this debate is that through its' resolution that 'brown-trouser moment' may just be avoided.
I avoid the so called debate because i dont understand it and want to learn, but i now feel the need to ask my own questions as the bickering has clouded the original facts whether they were right or wrong.
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Old 31st July 2003, 09:00 PM   #158 (permalink)
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Quote:
Originally posted by Mycroft
Ahh, I see where you are confused OK,

200lb downforce gives 280lbs of sideways resistance on those graphs [roughly]...

At 400lbs there is 560lbs the ratio of the difference remains the same, however with every doubling on the downforce [200-->400] there is doubling of the grip [280--->560]

Can you see that? As one doubles so does the other, the ratio of adherence remains at 1.4 / 1.5 but the grip doubles as the weight doubles.

These graphs were presented as proving that the grip lessens immediately from 1kg... they do not do this they clearly show what I have said all along, 'only after the tyre reaches its optimum adherence/weight limit will the tyre start to show diminishing returns for the weight applied.
I'd confused myself for a moment.


...but, surely the amount of grip will at best be "very slightly" less than doubled and get progressively less than doubled as you keep loading the tyre. (If that makes sense, this is what I was trying to get at in a previous posting I think, I've slept since then).
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Old 31st July 2003, 09:07 PM   #159 (permalink)
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This is debate, there is no bickering here...

We are 'stalled' at the moment due to the 2 only slightly divergent views that persist and are yet to be resolved.

It is healthy and fun to debate with passion and not result to a handbags at dawn stance... I return to my Computer each day with real enthusism for the days to and fro... you must look at the evidence and proofs provided, you can then either go off and wait for us to resolve this finally and move on or put your view into this, you may see the graphs in one light or the other, if you have time to give it proper consideration then your input has value, and we all listen.

[Then we slag you off mercilessly ]
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Old 31st July 2003, 09:14 PM   #160 (permalink)
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Quote:
Originally posted by Thorin
...but, surely the amount of grip will at best be "very slightly" less than doubled and get progressively less than doubled as you keep loading the tyre. (If that makes sense, this is what I was trying to get at in a previous posting I think, I've slept since then).
The graphs don't show that and they were presented as proof, real tangible proof, they are not.

Now, with new tyre technology hitting the road every day i can assure you that chart is well out of date, you can check this your self in the link I posted on here showing how to do your own static friction test the results showed that modern tyres will give results closer to 1.7G. the line is effectively straight.
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