How stiff are F1 tyres?

[autogyro]

Not another cop out by a wizard of tyre technology JT.
Not much help with a primary technology focus is it.

[speedsense]

JT, is absolutely correct. Having spent a fair amount of time with assorted racing tire companies tires (not F1 however). You can have two (from two companies) tires exactly the same size, radial in design, of "similar" compounds and in terms of tire stiffness (tire vertical compression stiffness, checked in the same way you check springs..measuring deflection). The two tires will come up very different in spring rates. This is like comparing Green apples to Red ones. Almost comparing an orange to an apple.

Now comparing tires from the same company when it comes to tire construction (major consideration in spring rate).. if the company has not changed the belt construction or the materials used in the construction and simply made the tire smaller in width, it would stiffen the spring rate of the tire... if they changed the construction of the tire, they could leave the spring rates the same by design or increase them. If it was only a size change, then I too cannot see anything but a small percentage of change in spring rate.
It is logical and most likely Bridgestone has changed it's construction to account for the higher weight of the car rather than simply reducing it's size.

It was stated in this thread, that a stiffer construction tire on a low grip surface would somehow cause a higher internal temp. IMHO, I have never found this to happen and actually found the opposite to be true, because the low grip/stiff construction causes higher EXTERNAL heat, due to more sliding of the stiffer construct. This takes much longer for the heat to "migrate" from the outside to the inside. I believe the wearing of the tires at Montreal to be because of the external heat acquired more rapidly than the internal heat. This imbalances the heat cycle of the tire and tears the compound away due to the internal rubber running a cooler temp. Hence the balls of rubber present off line...
Because the "work" of the tire through movement and contortion of the belts from acquiring max slip angles, braking event contortions and accelerations are the major causes of heat internally. Brake use also causes the wheels to heat up and radiates that heat to the core of the tire by way of heating the internal air and the cords connected to the wheel. But the major supply of internal heat is the actual work of the tire itself.

Simply put, a low grip surface causes less of this to happen and causes heat to the tire, externally "first" then migrates to the inside.
Most tire companies do not give out this kind of information and most companies take back the used tires as not to give their competitors any ideas of what they are up too. For instance, if you have a tire deal with Michellin you cannot even take the tire off the rim yourself, the take offs are taken right away and if a tire disappears they send out a S.W.A.T. team to go find it...

[Jersey Tom]

Not another cop out by a wizard of tyre technology JT.
Not much help with a primary technology focus is it.

It's just immensely more complicated than most outside the industry can imagine.. and there are misconceptions and poor anecdotal evidence regarding everything.

There are probably still lots of people who think that temperature spreads across the tread is the way to set camber and pressure.

[speedsense]

Not another cop out by a wizard of tyre technology JT.
Not much help with a primary technology focus is it.

It's just immensely more complicated than most outside the industry can imagine.. and there are misconceptions and poor anecdotal evidence regarding everything.

There are probably still lots of people who think that temperature spreads across the tread is the way to set camber and pressure.

Most of those people have never used IR sensors, internal pressure/air temp sensors which change your perception of how this needs to be done and how manual tire pyro readings can be corrupted and do not understand tire heat migration with rubber

[WhiteBlue]

It was stated in this thread, that a stiffer construction tire on a low grip surface would somehow cause a higher internal temp. IMHO, I have never found this to happen and actually found the opposite to be true, because the low grip/stiff construction causes higher EXTERNAL heat, due to more sliding of the stiffer construct. This takes much longer for the heat to "migrate" from the outside to the inside. I believe the wearing of the tires at Montreal to be because of the external heat acquired more rapidly than the internal heat.

That was exactly what I have concluded as well. I think you read just the opposite of what you thought you read.

marcush, the Montreal tyre situation was absolutely consistent with the diagnosis of a carcass with too much stiffness compared to the extremely slippery asphalt. The tyres develop no grip that enables them to generate internal heat. The slip causes contact layer over heating and graining.

[autogyro]

So wouldnt your time and expertise be better spent trying to find a simplified way to explain to other engineers of other disciplines.
Tyres are hugely important to the over all car design and set up.
It is of little help just basking in the difficulty of the subject JT.

[speedsense]

It was stated in this thread, that a stiffer construction tire on a low grip surface would somehow cause a higher internal temp. IMHO, I have never found this to happen and actually found the opposite to be true, because the low grip/stiff construction causes higher EXTERNAL heat, due to more sliding of the stiffer construct. This takes much longer for the heat to "migrate" from the outside to the inside. I believe the wearing of the tires at Montreal to be because of the external heat acquired more rapidly than the internal heat.

That was exactly what I have concluded as well. I think you read just the opposite of what you thought you read.

marcush, the Montreal tyre situation was absolutely consistent with the diagnosis of a carcass with too much stiffness compared to the extremely slippery asphalt. The tyres develop no grip that enables them to generate internal heat. The slip causes contact layer over heating and graining.

yep, missed the word "no"...

[speedsense]

So wouldnt your time and expertise be better spent trying to find a simplified way to explain to other engineers of other disciplines.
Tyres are hugely important to the over all car design and set up.
It is of little help just basking in the difficulty of the subject JT.

Tires are the holy grail when it comes to suspension design and setup. If only drivers had as much compliance as a tire, the racing world would be far easier to engineer

[Jersey Tom]

Most of those people have never used IR sensors, internal pressure/air temp sensors which change your perception of how this needs to be done and how manual tire pyro readings can be corrupted and do not understand tire heat migration with rubber

Even IR sensors... not very straightforward using them for setup. Some believe in the "get an even spread mid corner" approach. I don't.

So wouldnt your time and expertise be better spent trying to find a simplified way to explain to other engineers of other disciplines.
Tyres are hugely important to the over all car design and set up.
It is of little help just basking in the difficulty of the subject JT.

Some things are confidential and I can't discuss publicly. Anything that can be shared on this forum is pretty basic and/or public domain and/or opinion and/or conjecture.

Other stuff is just poorly understood, by just about everyone. Includes myself. Really, test data is the only thing you can go off, and even then you have to be able to take it with a grain of salt.

Point I was trying to get at earlier, is just saying that the front tires are "stiffer" doesn't say much if anything. Even if I knew everything about their F1 tires from last year and this year.. the materials, the angles, the mold profile, the compounding.. it's pretty tough to conclusively say what it's gonna do to the car.

[Belatti]

Even IR sensors... not very straightforward using them for setup. Some believe in the "get an even spread mid corner" approach. I don't.

There are probably still lots of people who think that temperature spreads across the tread is the way to set camber and pressure.

What is your opinion about these kind of infrared cameras?

http://www.irisys.co.uk/thermal-imaging ... heets.aspx



There was an article about them in an RCE mag (november 2005):

Of course the issue of capturing rivals’ tyre temperatures is a very
relevant one in series like A1 Grand Prix, GP2 or even F1, and it’s not
surprising that a number of Formula 1 teams expressed an interest in the
imager when Racecar approached them. However, equally unsurprisingly,
they were not happy with the results being published

Still you can get on of those, go to the pits and take pics of them, whats all the "dont publish fuzz" about?

[ubrben]

So wouldnt your time and expertise be better spent trying to find a simplified way to explain to other engineers of other disciplines.
Tyres are hugely important to the over all car design and set up.
It is of little help just basking in the difficulty of the subject JT.

Tyres are simply not well enough understood to make the sort of generalisations you're asking for.

This is why tyre companies do s***loads of testing.

I'm sorry if that's not an acceptable answer, but it's the reality.

Ben

[speedsense]

Most of those people have never used IR sensors, internal pressure/air temp sensors which change your perception of how this needs to be done and how manual tire pyro readings can be corrupted and do not understand tire heat migration with rubber

Even IR sensors... not very straightforward using them for setup. Some believe in the "get an even spread mid corner" approach. I don't.

Would depend on the goal that is trying to be achieved, the type of tire and the chassis used and the type of racing. There's a fundamental difference in reading and use of data on an oval car with a "full" oval set up vs a road racing car especially with tire readings and the use of the data. For instance, in oval cars, the temp balance between the front and rear on the right side and on the left side of the car is far more important than the spread across a single tire.
And to add to this, the techniques and experience of the individual analyzing the data. 85% of data analysis used is founded in "absolute number analysis" yet absolute analysis has the least "impact" on a team's performance. (Though to an engineer is of the up most importance in fulling math equations)
There are techniques in data that are far more advanced and have a great amount of impact on not only the car's performance but the drivers as well. But those techniques are used by but a very small percentage of those that do it for a living. And to a degree that is the difference been a consistent front running car and one that gets there once and while...

[Jersey Tom]

Even IR sensors... not very straightforward using them for setup. Some believe in the "get an even spread mid corner" approach. I don't.

There are probably still lots of people who think that temperature spreads across the tread is the way to set camber and pressure.

What is your opinion about these kind of infrared cameras?

http://www.irisys.co.uk/thermal-imaging ... heets.aspx



There was an article about them in an RCE mag (november 2005):

Of course the issue of capturing rivals’ tyre temperatures is a very
relevant one in series like A1 Grand Prix, GP2 or even F1, and it’s not
surprising that a number of Formula 1 teams expressed an interest in the
imager when Racecar approached them. However, equally unsurprisingly,
they were not happy with the results being published

Still you can get on of those, go to the pits and take pics of them, whats all the "dont publish fuzz" about?

After having read some.. debatable articles, some stuff in RCE is good, some not.

Thermal cameras... I mean it's the same concept as the individual IR sensors. Depending on what you're doing with it, it can have some value or be worthless. Can't get into the specifics of it.

Teams don't want to make life any easier for their competitors though, to your point of why they don't like things published. Anything that characterizes their car.

+1 to Ben's post though.

[marcush.]

as long as it improves lap time I don´t care about the temp spread or pressures ...but at times this might infere with recommendations from the tyre supplier..so
you are on a thin rope there..

as always it seems ,the more you know the more you know what you don´t know..so for someone with almost nil knowledge even pressure and IR temps measured with a cheap gun is satisfactory as they are unable to draw any useful conclusions from their findings or think they have found out..
But as you dig in deeper and need more info to make reliable prdictions it seems
at least to me things get more complicated than anyone really can calculate or simulate with decent repeatability on track.

[autogyro]

Not good enough then is it.