Pirelli's poor consistancy a reflection of their road tires?

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Jersey Tom
Jersey Tom
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Re: Pirelli's poor consistancy a reflection of their road ti

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Sayshina wrote:and just about every suspension guy who's ever spoken up on the subject has said tires would look very different if they were allowed to.
Oh I'm sure "suspension guys" think they know a lot about what they want and need out of a tire, or how to get it :) I've had plenty of those conversations before.

"Well if you guys would do X, the tire would do Y."
"Doesn't work like that."

But I'm not gonna get too much into this. I'm not a tire company engineer anymore, and I'm f'in tired.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

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strad
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Re: Pirelli's poor consistency a reflection of their road ti

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Maybe I worded it wrong...They have used these sidewalls and designed the car and it's suspension around them. IF you were to change the sidewall you would have to completely redesign the suspension, and that is not something they seem to be inclined to want to do just now.
To achieve anything, you must be prepared to dabble on the boundary of disaster.”
Sir Stirling Moss

Sayshina
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Re: Pirelli's poor consistency a reflection of their road ti

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strad wrote:Maybe I worded it wrong...They have used these sidewalls and designed the car and it's suspension around them. IF you were to change the sidewall you would have to completely redesign the suspension, and that is not something they seem to be inclined to want to do just now.
Well, actually yes, but all indications are it's the aerodynamics that teams are terrified of changing. The specific demands they made of Pirelli seem to be mostly about the aero shape of the tires at speed, and the requirement for them to exactly mimic the Bridgestones.

Jersey, I realize you've indicated you no longer wish to debate this, but really. We've seen this same debate throughout the history of the automobile. The engine guy wants the engine to be the overriding factor, and the chassis guy says he can't package that or can't use that powerband, and wants the engine guy to conform to his concepts.

I never meant to imply that the suspension guys should be blindly followed, but you have to admit that even on a F1 car suspension is still necessary. And if it's necessary then they get to have an input. It's no more fair to say suspension should be dictated by tires than to say the opposite.

Your implied claim is that current F1 tires have intrinsic value outside of the current regs, and that even with more open regs they could continue to be constructed in a similar manner. Would you care to elaborate? Why then did Michelin want different regs, specifically aspect ratio? In what way are the suspension guys fundamentally wrong in their predictions?

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godlameroso
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Re: Pirelli's poor consistancy a reflection of their road ti

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You would have to change the suspension and the packaging if you used larger wheels, even if the wheel tire combo was still the same overall dimension. First the way the wheel hub gets loaded changes, second you need better control over suspension travel as well as more of it, this plays havoc on an f1 car's super ride height sensitive floors. You would have to redesign the steering rack, control arms, uprights, suspension packaging, brake ducts and that's just off the top of my head I'm sure it affects other things which I'm not smart enough to realize.
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Sayshina
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Re: Pirelli's poor consistancy a reflection of their road ti

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godlameroso wrote:You would have to change the suspension and the packaging if you used larger wheels, ...

..., second you need better control over suspension travel as well as more of it, this plays havoc on an f1 car's super ride height sensitive floors.

You would have to redesign the steering rack, control arms, uprights, suspension packaging, brake ducts and that's just off the top of my head I'm sure it affects other things which I'm not smart enough to realize.
Yes, you would need to redesign the suspension specifics, but no more so than when you raise the nose or go to or away from a keel design. Actually, almost certainly a lot less change would be required. You would need to redesign the hubs, but teams seem to do this almost every year regardless. Of the other things mentioned, teams sometimes change brake ducts at nearly every race.

You note that suspension travel would need to increase, but fail to note why. Currently the F1 tire performs a huge chunk of the suspending, and there is no way to reduce this. Almost all suspension guys, most car designers in general (across formulae) and even some tire guys have said that the tire does a relatively crap job of suspending the car. Most of them have said over the years that you would expect to gain more control over the car by increasing the amount of suspending done by the suspension.

This is in fact the implied argument I almost had with Jersey Tom. He would seem to disagree with the above.

Jersey Tom
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Re: Pirelli's poor consistancy a reflection of their road ti

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The beef I have is that you've made a number of generalized and blanket statements without anything to back it up.

As a professional "race tire and suspension [dynamics] guy," that raises red flags for me.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

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Ciro Pabón
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Re: Pirelli's poor consistancy a reflection of their road ti

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Sayshina wrote:... use a more modern construction, similar to what you see in other high performance tires (IE., much shorter sidewall, very different aspect ratio) and larger wheels.
Well, I actually liked those "modern" tyres.

[youtube]http://www.youtube.com/watch?v=fAkPMuNvTMA&NR=1[/youtube]
Ciro

riff_raff
riff_raff
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Re: Pirelli's poor consistancy a reflection of their road ti

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JT,

Here's a question you might be able to answer. Being a hand made product, how consistent are race tires structurally from one to another? And is there any way the manufacturers check them for consistency in structural characteristics?

Thanks.
riff_raff
"Q: How do you make a small fortune in racing?
A: Start with a large one!"

myurr
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Re: Pirelli's poor consistancy a reflection of their road ti

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Can I just say, congratulations to Pirelli for getting the tyres just about right for this event. We had a good mix of strategies, good differentials between the cars, overtaking, and no real problems or people whose performance dropped completely off a cliff. Bravo!

Jersey Tom
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Re: Pirelli's poor consistancy a reflection of their road ti

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riff_raff wrote:JT,

Here's a question you might be able to answer. Being a hand made product, how consistent are race tires structurally from one to another? And is there any way the manufacturers check them for consistency in structural characteristics?

Thanks.
riff_raff
Like any hand made product, it's somewhat a function of the quality of the equipment and the skill of the builder. And yes, there are ways of checking for variation.
Grip is a four letter word. All opinions are my own and not those of current or previous employers.

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747heavy
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Re: Pirelli's poor consistancy a reflection of their road ti

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myurr wrote:Can I just say, congratulations to Pirelli for getting the tyres just about right for this event. We had a good mix of strategies, good differentials between the cars, overtaking, and no real problems or people whose performance dropped completely off a cliff. Bravo!
+1, well done Pirelli so far
"Make the suspension adjustable and they will adjust it wrong ......
look what they can do to a carburetor in just a few moments of stupidity with a screwdriver."
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747heavy
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Re: Pirelli's poor consistancy a reflection of their road ti

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riff_raff wrote: And is there any way the manufacturers check them for consistency in structural characteristics?

Thanks.
riff_raff
Sure JT and Ben will know more about it, but this is perhaps a way to check the finished tire, for uniformity of radial stiffness.

http://www.vibratesoftware.com/html_hel ... 0VARIATION

not sure, if they can test/correct during the build process of the tire, or just exclude tires outside the tolerance during final QC.

I seem to remember that (some) NASCAR/Stockcar teams make a bit of an dance about it, and testing for sidewall stiffness
"Make the suspension adjustable and they will adjust it wrong ......
look what they can do to a carburetor in just a few moments of stupidity with a screwdriver."
- Colin Chapman

“Simplicity is the ultimate sophistication.” - Leonardo da Vinci

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strad
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Re: Pirelli's poor consistancy a reflection of their road ti

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I'm glad you guys liked it. It played out just I susspected and it sucked.
To achieve anything, you must be prepared to dabble on the boundary of disaster.”
Sir Stirling Moss

myurr
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Re: Pirelli's poor consistancy a reflection of their road ti

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strad wrote:I'm glad you guys liked it. It played out just I susspected and it sucked.
In what way, other than your beloved Ferrari doing badly, did this race and more specifically the tyres suck?

nacho
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Re: Pirelli's poor consistancy a reflection of their road ti

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Pirelli switched tires?
"The most important thing to be said is that every result this weekend, whether positive or negative, has a common cause: the Pirelli tyres," Trulli wrote in a column for Repubblica.

"They've left us all shocked. I don't mean they were better or worse than we had expected, I mean that they were completely different: it's as if they have been changed since the last tests in Barcelona.

"During the winter all of us, in every team, have worked with tyres that would deteriorate immediately. It was a characteristic of the tyres, and there's been some polemics too. So we had thought the problem was to make them last long enough.

"Instead here in Melbourne we've found ourselves with tyres that had no durability problems, but in exchange for that they would struggle immensely to get up to temperature."

"If the tyres don't get up to temperature it's impossible to get the performance," he said. "During the race only two drivers had no problem getting the tyres up to temperature: [Lewis] Hamilton and [Sebastian] Vettel, second and first.

"Everyone else, some more than others, struggled. Even [Mark] Webber. In my opinion it's the same reason why Ferrari did badly in qualifying."