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I'm pretty p1ssed off that we've ended up bickering again - not least because my name's been dragged into it.

I hope the respected field experts refrain from feeling this site is the haunt of bored school children with impressive resumes.

Cem.
 

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Discussion Starter #323
Co-efficient of Friction... what does that mean?

I can tell you what it doesn't mean, although many of you will think it does, it does not mean grip.

It means the exact opposite... it means slip.

Some of you don't believe me do you?

Ok, look at it this way...

You intend to climb a Mountain, you buy some ropes, you intend to grip these ropes and climb up, you won't make it if your hands slip, and when you do you get... FRICTION burns. we rub off skin, much as the tyre loses rubber...

The clasping action of our poor climber is the same as plain old weight bearing down on tarmac.

Grip = 0 slip.

Let's carry on with this simple analogy, when our climber was doing well he would clasp the rope get sufficient grip to haul himself up and proceed this way to the top, if he then on the next climb had to carry more weight he would have to clasp harder, the Newtownian Physics tells us that as his burden increases he must clasp harder, an equal amount strangely :D, at some point no matter how much harder our hapless climber clasps the burden will drag him down at that point he is at the mrecy of FRICTION, until that point friction played no real part in his climbing what he had was ADHERENCE [mentioned by me earlier] and CONFORMITY [also mentioned only by me], adherence meant that his hand was 'glued' to the spot, conformity in that his skin was pressed harder and harder into the rope pattern, into the INTERSTICES [remember them]

So Simons statement:-

'...(simply put). Doubling the weight on a tyre, does not double it's grip.

Was wrong, is wrong and can never be right.

Please refer to these, use the numerous references within:-
http://www.racer.nl/reference/pacejka.htm

I run this program and so do many in the industry as it is about the easiet.
http://www.adams.com/product/product_line/tire.pdf

This one is my favourites:-
http://www.informs-cs.org/wsc00papers/135.PDF

Finally a quote from someone respectede throughout the tyre World:-

Tires should be as wide, as well as tall, as possible, to allow the largest possible footprint/contact patch to the ground as possible. The R*mu equation only holds good for the actual sliding condition; regular/before slide conditions actually quasi-stationary, since contact-patch (individual rubber blocks) are stationary relative to their nground counterpart area. Therefore, approx. and up to double the adhesion coeff. (mu) can be expected (non-sliding). Inbetween non-sliding and fully-skidding, the descibtor is the skid/slip-angle (phi), the angle between the zero-slip line of the tire, and the actual movement direction of the tire.

See also 'Rubber Science & Technology' and other, for further in-depth and newest research results.

Sincerely,

Soeren Algreen-Ussing, Denmark

That is a direct quote from him to you all here.

---------------------------------------------------------------
 

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Mycroft,

What I find remarkable is how you see fit to doubt and challenge the words of respected and proven technical engineers?

I think the single biggest problem you have is your 'hidden' entity. Almost every regular user on this forum knows each other by face, if not on a first name basis, yet nobody has ever met you.

Perhaps it's the first step we need to take to get everyone to believe in you a little more?

I'd love for you to prove to everyone that you aren't just a very clever 'bot' ;)

Cem
 

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Discussion Starter #328 (Edited)
Cem, the fact is that the statement is wrong, it is proven wrong everywhere, it is just that people including aparently 'respected' engineers are not as infallible as they would have you imagine.

The statement as outlined by Simon is wrong.

Mark you should read the above not just act so foolishly.
 

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Apart from anything else, how can you expect to be taken seriously with a sig like this:

Simple Simon went a-fishing, For to catch a whale; But all the water he had got, Was in his mother's pail.

He went for water in a sieve, But soon it all fell through; And now poor Simple Simon Bids you all adieu.

Extract from the ''Mycroft Book of the Dead''
WTF?
 

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Discussion Starter #330 (Edited)
Mark,

The sig is purposeful, Simon is not here in some altruistic bout of largesse he is here because he is as hurt as some others around here.

The sig just shows it in stark relief.

Now, read the proofs, you will find that Simon and all the rest who have argued against what I have sad is wrong...

Everyone keeps asking for proofs... well there they are, start reading.
 

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Discussion Starter #331 (Edited)
I believe Simon is a bit of a racing driver, it is rather bad news that he is unable to differentiate between grip and slip, grip never kills you, slip does.

:D

FYI

I had a similar thing to this happen on the Scooby-net, this is the reason maybe for Simons sudden appearance here, I pulled up a few people who forgot to differentiate between 'Rebound' and 'Rebound rate' that lead to some rather red and embarrassed faces too... :D

In the end we had to get Koni to confirm what I had said.

Incidentally, that was the start of my ejection from the Scooby-net, from that moment on the die was cast as was his appearance with a gang of squawkers on here.
 

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Hi All

Have just popped back to say, as usual... If anyone believe Mycroft has said anything that requires answering, please let me know.

In the mean time, you may find it interesting to read the following thread (on scoobynet, apologies Cem, hope you don't mind)..

http://www.scoobynet.co.uk/bbs/thread.asp?ThreadID=235738&Page=2

Start off with Ettore's post towards the end of the page (assuming it hasn't been edited by now).

What a shame it's come to this.

All the best

Simon
 

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Discussion Starter #333
I shall go and slap Tor for that, this is my arguement.

Simon, I see you again avoid the issue rather than engage in it.

So tell us, have you confused Grip with Slip?

To answer your mate Telboy as you can't/won't...

He asks:-

''So all this talk of "optimum point" is irrelevant?''

No, the thing is that at some point no matter how hard you squish the rubber onto the road forcing it into all the little nooks, crannies and crevices there comes a point where there is no more grip to be found, that is the point where on the grip/load scale the lines diverge, this 'conformity' limit is also responsible for the reduction in the real Co-Efficient of friction when the tyre does slip with heavier loads...

Simple eh? Simon?
 

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Mycroft

Just so you are aware, I've read the first line of the above post, and no more. This is what I have done with your posts for about the last 5 pages.

If there is something in there for me to answer, you will note that I have simply replied to your previous posts by asking if anyone ELSE thinks you have said anything worth responding to.

Otherwise I'll just assume they are ignoring you as I am.

Regards

Simon
 

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Discussion Starter #335 (Edited)
I have 'slapped' Tor for his interruption, but he has just asked me to post this...

>dictation<

Simon, could you tell us all when a disc brake has a pad with a Co-eff of 0.45 and is slowed down by it does it mean, assuming flat ground, when the driver has stopped is he holding the car stationary with that same co-eff or is it infinite?

>end of dictation<
 

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LOL...

>dictation<

Simon, could you tell us all when a disc brake has a pad with a Co-eff of 0.45 and is slowed down by it does it mean, assuming flat ground, when the driver has stopped is he holding the car stationary with that same co-eff or is it infinite?

>end of dictation<
Do you know... the only time I've ever seen someone else use >these< in that way is someone called Vinegar. who has posted in huge support of you on scoobynet (see that link again). :rolleyes:

Oh Mycroft, PLEASE, it's starting get really embarrasing now.

Cheers

Simon
 

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Discussion Starter #337
I use them all the time, 'Vinegar' is the same fella as 'Salt' and 'Pepper' the 'condiment set' off the 'Scooby-net'... :D

Please answer the question there are dozens of watchers and you never klnow you could redeem yourself.
 

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Discussion Starter #339
To answer your friend on 'page 3' who asked this:-

''Ettore - I thought your friends name was Dr Ing Wilstshire and yours is Dr Ettore Bakker - so why have you signed off your posting Dr Ing Bakker?!?!?!? ''


Answer:-

'Dr. Ing.' is my title in Europe, it sorta means Doctor of Engineering... I am titled Dr. Ing. Wiltshire, Tor is Dr. Ing. Bakker.

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The same chap asked:-

''Why the **** would anyone confuse grip for slip - complete fecking opposites aren't they!!!

Answer:-

Yes, but not to some eh? Simon?
 
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