2018-2020 Tyres Thread

[godlameroso]

Suggestion: change the name of the thread to reflect that it's still relevant to the current 2021 tyres.

[...]
Are there any other circuits on the calendar?

There's 20 other circuits on the calendar.

But in all honesty ... why did you quote that post when what you wrote had absolutely nothing to do with it?

Because I wanted to know what you think....

[RZS10]

But why are you interested in my input in particular? I don't have anything useful to add, if i had i would do so but all i can do is speculate and do some (un)educated guesswork but i usually prefer not to talk out of my ... behind

In theory though: assuming that Pirelli isn't full of it, then some teams might have been playing around with pressures or other things related to how they run the tyres, even though Pirelli claim they set the pressures with safety margins in mind ... who knows how far below the min. starting pressures the teams could get.

I think it's fair to assume that if anyone was doing some funky business with tyres in Baku then they would have done so in previous races and most probably also in previous seasons - so it's another fair assumption that the differentiating factor between seasons would be the change of the tyre construction itself and within this season it would be the track.

So yeah ... believing that the tyre failures last year were really just down to debris then it might very well be the case that the current tyres were not reinforced/adjusted enough for the increased weight of the tread, at least in certain running conditions which this track's characteristics could have provided.

[godlameroso]

But why are you interested in my input in particular? I don't have anything useful to add, if i had i would do so but all i can do is speculate and do some (un)educated guesswork but i usually prefer not to talk out of my ... behind

In theory though: assuming that Pirelli isn't full of it, then some teams might have been playing around with pressures or other things related to how they run the tyres, even though Pirelli claim they set the pressures with safety margins in mind ... who knows how far below the min. starting pressures the teams could get.

I think it's fair to assume that if anyone was doing some funky business with tyres in Baku then they would have done so in previous races and most probably also in previous seasons - so it's another fair assumption that the differentiating factor between seasons would be the change of the tyre construction itself and within this season it would be the track.

So yeah ... believing that the tyre failures last year were really just down to debris then it might very well be the case that the current tyres were not reinforced/adjusted enough for the increased weight of the tread, at least in certain running conditions which this track's characteristics could have provided.

Because then I can see where you stand, and I largely agree so will say no more on the subject. Because I feel there's nothing further to discuss.

[RZS10]

Fair enough

[...]
assuming that Pirelli isn't full of it
then some teams might have been playing around with pressures or other things related to how they run the tyres
who knows how far below the min. starting pressures the teams could get.
[...]

They weren't.
Yes and yes.
Apparently 1.5 to 2 psi below the safety margin.

Isola:

"The different scenario is that mainly the tyres were running at a lower pressure compared to the expectation, and it was not just the lower pressure, there were also other elements in the equation, that created the failure."

"Isola has suggested that for the tyres to have operated safely on the Red Bull and Aston Martin cars, with hindsight a further 1.5-to-two psi should have been recommended."

https://www.gpfans.com/en/f1-news/66260 ... n-in-baku/

Given that they will probably keep minimum starting pressures a lot higher for the remainder of the season i wonder who will benefit or be hurt by that the most.

[ispano6]

Interesting take and insinutes that RedBull might have been pushing things a little...
https://www.racefans.net/2021/06/15/ext ... -in-spain/

I’m sure that sly dig at RedBull will be enough to make some of the poster’s here explode

Interesting that Hamilton is so keen to call out Red Bull's practices now that their team is threatened.
Reminds me how Ferrari called out Mercedes controversial wheels that acted as a heat sink and was used for several year's in various guises. When they covered the holes just to be on the safe side of a protest being lodged, their performance that weekend went down.

[sovietskaye]

Can anyone tell me if the current revision FIA technical directive relating to tyre operation (TD003) is a publicly available document, and if so point me to where I might be able to access it?
Cheers

[Marble]

I have seen Pirelli cool down pattern, and I have tried to find it by myself using Gay-Lussac law, but I don't know why, I don't get to same coefficient.

For the front tyre, Pirelli has :
PSIf = (T(°C) - 100) * 0,108 + PSIstartf (PSI and °C)

If we use Gay Lussac (or perfect gaz law) we have (Pascal and Kelvin)

Pstart / T start = P / T

ie

P = (Pstart/Tstart)*T
P = (Pstart/Tstart)*T - Pstart + Pstart
P = (Pstart/Tstart)*T - Pstart*(Tstart/Tstart) + Pstart
P = (Pstart/Tstart)*(T-Tstart) + Pstart

And there we have the same form as the Pirelli formula but using Pascals and Kelvin ie in PSI and °C for the fronts

P = (PSIstart*6895)/(T°start+273)*(T°+273-T°start-273) + Pstart
P = PSIstart*(6895)/(T°start+273)*(T°-T°start) + Pstart

Replacing by numeric numbers for PSIstart and T°start for the fronts I have :

P = 21*6895/373*(T°-100) + Pstart
P = 388,19*(T°-100) + Pstart

And finally transforming into PSI :
PSI = 388,19/6895*(T°-100) + PSIstart
ie
PSI = 0,0563*(T°-100) + PSIstart

Problem is I don't get the same coefficient as Pirelli (0,056 vs 0,108)
Where is my mistake ?

[Chuckjr]

Taken from another thread...

Why do they raise the pressure when they are worried...

Is it that a tyre with less pressure is structurally softer and has more movement and more 'fatigue'?

As a tyre rotates, the part in contact with the road is flattened - that's what the contact patch is. In order for that flattening to occur, the sidewall has to deflect and there is a lot of hinging at the point where the sidewall and the tread meet. And just like getting a piece of plastic and flexing it back and fore lots of times very quickly will heat up the plastic at the flex, so the tyre sidewall / shoulder will heat up.

At 300kmh, the tyre is rotating approx. 40 times per second (83.33m/s / (pi*0.66m)), so the shoulder flexes 40 times a second too but as it flexes one way and then back to "normal", it actually has 80 distinct movements per second. That's a lot of energy being put into the tyre shoulder. If you increase the pressure in the tyre, this deformation is reduced meaning there is a bit less flexing and thus less heating of the critical shoulder area.

Just a fan, thank you for that great explanation.

Is there a reason why they have not gone to something like this? Wouldn’t it offer greater potential feedback to the driver and the suspension systems since there’s no air compliance factor? And we would never have flats again.

http://thedapperdarling.blogspot.com/20 ... s.html?m=1

[RZS10]

Those prototypes were never brought to production for road cars, so it's only fair to assume that they wouldn't work for an F1 car.

[Hoffman900]

Interesting take and insinutes that RedBull might have been pushing things a little...
https://www.racefans.net/2021/06/15/ext ... -in-spain/

I’m sure that sly dig at RedBull will be enough to make some of the poster’s here explode

Interesting that Hamilton is so keen to call out Red Bull's practices now that their team is threatened.
Reminds me how Ferrari called out Mercedes controversial wheels that acted as a heat sink and was used for several year's in various guises. When they covered the holes just to be on the safe side of a protest being lodged, their performance that weekend went down.

Uh yeah. If I was in the battle for a championship and I saw my competitors doing some funny business, I would absolutely call them out on it.

Why do people take it as a slight with Lewis calling out RedBull for this stuff? Max can do the same...

[Zynerji]

Interesting take and insinutes that RedBull might have been pushing things a little...
https://www.racefans.net/2021/06/15/ext ... -in-spain/

I’m sure that sly dig at RedBull will be enough to make some of the poster’s here explode

Interesting that Hamilton is so keen to call out Red Bull's practices now that their team is threatened.
Reminds me how Ferrari called out Mercedes controversial wheels that acted as a heat sink and was used for several year's in various guises. When they covered the holes just to be on the safe side of a protest being lodged, their performance that weekend went down.

Uh yeah. If I was in the battle for a championship and I saw my competitors doing some funny business, I would absolutely call them out on it.

Why do people take it as a slight with Lewis calling out RedBull for this stuff? Max can do the same...

Historically, Mercedes have boasted that they "Do not look to the left or the right, just straight ahead", implying that they don't care what the competition is doing. Once threatened, however, that seems to change very quickly.

[Hoffman900]

Interesting that Hamilton is so keen to call out Red Bull's practices now that their team is threatened.
Reminds me how Ferrari called out Mercedes controversial wheels that acted as a heat sink and was used for several year's in various guises. When they covered the holes just to be on the safe side of a protest being lodged, their performance that weekend went down.

Uh yeah. If I was in the battle for a championship and I saw my competitors doing some funny business, I would absolutely call them out on it.

Why do people take it as a slight with Lewis calling out RedBull for this stuff? Max can do the same...

Historically, Mercedes have boasted that they "Do not look to the left or the right, just straight ahead", implying that they don't care what the competition is doing. Once threatened, however, that seems to change very quickly.

Well, if they said that before, that's dumb, but it's also silly that fans take every little thing at their, the driver's, the team principal's word. That goes for all the teams. Mercedes know they need to be looking everywhere, they always have and always do.

*Newsflash* they're just spewing bs in the media half the time. It gives the reporters something to write about and fans to eat up.

Back to on topic, I'm still surprised Pirelli didn't have a handle on the tire pressure thing.

[Zynerji]

Uh yeah. If I was in the battle for a championship and I saw my competitors doing some funny business, I would absolutely call them out on it.

Why do people take it as a slight with Lewis calling out RedBull for this stuff? Max can do the same...

Historically, Mercedes have boasted that they "Do not look to the left or the right, just straight ahead", implying that they don't care what the competition is doing. Once threatened, however, that seems to change very quickly.

Well, if they said that before, that's dumb, but it's also silly that fans take every little thing at their, the driver's, the team principal's word. That goes for all the teams. Mercedes know they need to be looking everywhere, they always have and always do.

*Newsflash* they're just spewing bs in the media half the time. It gives the reporters something to write about and fans to eat up.

Back to on topic, I'm still surprised Pirelli didn't have a handle on the tire pressure thing.

"We concentrate on ourselves. We don't look too much left and right and do the talking on the track. “If you try to beat each other and perform at the highest level and then you need equalization after the first race, you cry out after the first race, that's not how we've done things in the past." Toto Wolff - Mar 19, 2021

And Pirelli suffer from the same thing that the FIA rule-makers suffer from.... They simply are not as intelligent (combined) as the teams are at getting around restrictions. That is the fundamental flaw in F1 governance.

[Hoffman900]

Yeah, that was a dumb statement to make by Toto. He should really say "we're trying to win like everyone else and will do whatever it takes, including calling the rest of you out for what we perceived are grey area infractions".

[subcritical71]

I have seen Pirelli cool down pattern, and I have tried to find it by myself using Gay-Lussac law, but I don't know why, I don't get to same coefficient.

For the front tyre, Pirelli has :
PSIf = (T(°C) - 100) * 0,108 + PSIstartf (PSI and °C)

If we use Gay Lussac (or perfect gaz law) we have (Pascal and Kelvin)

Pstart / T start = P / T

ie

P = (Pstart/Tstart)*T
P = (Pstart/Tstart)*T - Pstart + Pstart
P = (Pstart/Tstart)*T - Pstart*(Tstart/Tstart) + Pstart
P = (Pstart/Tstart)*(T-Tstart) + Pstart

And there we have the same form as the Pirelli formula but using Pascals and Kelvin ie in PSI and °C for the fronts

P = (PSIstart*6895)/(T°start+273)*(T°+273-T°start-273) + Pstart
P = PSIstart*(6895)/(T°start+273)*(T°-T°start) + Pstart

Replacing by numeric numbers for PSIstart and T°start for the fronts I have :

P = 21*6895/373*(T°-100) + Pstart
P = 388,19*(T°-100) + Pstart

And finally transforming into PSI :
PSI = 388,19/6895*(T°-100) + PSIstart
ie
PSI = 0,0563*(T°-100) + PSIstart

Problem is I don't get the same coefficient as Pirelli (0,056 vs 0,108)
Where is my mistake ?

I learned gas law as PV over T (vs P over T). Without me doing any calculations could the inclusion of volume alter your coefficient? I think the answer is no based on yours being a factor of 2 off from Pirelli.