F1technical.net

Hush wrote:

hardingfv32 wrote:

ema00 wrote:harder tires works at hotter temperature, this is sure

Why?

Brian

I would also like to know. I was under the impression that the compounds operated optimally within the same temperature bracket with the only difference being the time it takes to heat the different compounds.

Maybe, the harder tyres operate better at a higher temperature which increases the stickiness of the compound. I don't know much tyres to be honest.

I don't remember tecnichally why, but I've seen a video that explained to me it.
However when a team has some difficults with hard tires (ferrari for example) we always say that the car isn't able to let the tires reach the right temperature, if soft and hard tires have the same excercise temperature why soft works well and hard doesn't? If it was only a time problem, tires would work only a bit later (7 lap? 8?) instead all the stint is slower than the other team without this kind of problem.

bitbp wrote:First of all. Hello everyone. Im new to this forum and glad to be here.

Now to the point.
Did anyone posted this?

https://p.twimg.com/AnAhQIcCQAAtu8-.jpg

Seems Ferrari at some point been using realy high tyre pressure. Thats Fernando Alonso (FA) tyre setup for a stint.

1.7 bar is quite high (I believe recomended its 1- 1.2)
Some people aims this means about 12-15% less grip and about 30ºC less in tyres.

If they have been using this tyre pressure for tests, it could explain why the car looks so nervous and has high degradation on tyres.
Ferrari could be playing with everyone to make other teams believe they are in "bad shape" when they are not...

It is pressure after a 26 lap stint so it is higher than the "rest" pressure.
Anyway I don't think you can trust this paper. It is common to modify the tyre numbers to avoid other teams to know what you do. They also do that in GP2. The only way to have the true number is to see it on the grid (and then you alert your team and ask them to drop pressure by 0.3 bar 2 minutes before race start )

Re: Tyre temps : a few pages back I already posted this link where you can see the optimal temps of the compounds ( for 2011 spec Pirellis ) :

http://www.aaformula1.com/2011/04/f1-pi ... stics.html

Of course , I don't know about the credibility of the source.

Nico says .8 Bar

strad wrote:Nico says .8 Bar

What is .8 bar?

gilgen wrote:

strad wrote:Nico says .8 Bar

What is .8 bar?

0.8bar = 80 kPa

gilgen wrote:

strad wrote:Nico says .8 Bar

What is .8 bar?

1 bar = 14.5 psi
hence
0.8 bar = 11.6 psi

for those who use psi.

Oh boy. Where to begin...

bitbp wrote:1.7 bar is quite high (I believe recomended its 1- 1.2)
Some people aims this means about 12-15% less grip and about 30ºC less in tyres.

Doesn't seem at all high to me. And recommended by whom? Pirelli? The tire company doesn't necessarily know what recommendation is best for any car or driver. As for the grip and temperature claims... a lot of people claim a lot of things. Also, a lot of people don't know what they're talking about.

Goran2812 wrote:aren't those tire temps really low? 90 degrees centigrade is the optimal working temp for them,right?

No, not necessarily. The whole line about having some set "optimal" temperature is a crock, IMO.

Hush wrote:I was under the impression that the compounds operated optimally within the same temperature bracket

Says who?

Mr.G wrote:I think it's like this, if the tyres must have the same diameter hard or soft type, the thicknesses of the "ruber" compound must be the same.

Not at all.

GrizzleBoy wrote:Well, you want the tyres to be "sticky"/"gummy"/"flexible" so that they can stretch as you put load on them and get the maximum amount of surface area on the road at all times.

Not at all true. If that were the case you'd just take all the air out of the tires. The hardness / stiffness of the tread rubber contributes dick all to the overall stiffness of the thing. It's a composite. Load is carried by the reinforcement, not the matrix.

Also, the whole bit of "harder" treads needing more heat to work right... I don't necessarily agree with.

ema00 wrote:However when a team has some difficults with hard tires (ferrari for example) we always say that the car isn't able to let the tires reach the right temperature

Drivers and other people addressing the public say stuff like this, which isn't necessarily true at all. Besides, the tires are pre-heated to whatever temperature the team wants. The set point temperature is reached before the car leaves the pits.

Thanks for piping in.

For all the Newbies out there, Jersey Tom is our resident tire expert. Think twice before challenging his tire related statements.

Brian

I was chatting with a tyre expert a short while ago and learned the following;
Racing slick tyres are compounded with a resin in the rubber. The resin is a glassy solid at temperatures below its melting point. However, when the resin melts it turns from a glassy solid into a viscous, sticky liquid - this is the phenomenon that people like Martin Brundle refer to as 'switching the tyre on'. If the driver is unable to get sufficient heat into the tyre it has almost no grip, hence the tyres being almost undriveable on cold tyres.

Once the tyre is at the correct operating temperature it transforms into a sticky and very grippy tyre, but if you overheat it the compound will just slide off the tyre and the grippy part of the tyre will disappear very quickly, very soon the tyre will be down to the carcass. The rubber compount is left on the track, either as marbles or the 'rubbering in' of the track.

Several times I have heard Coulthard and Brundle talking about tyres having a chemical bond to the track surface. this is certainly not the case... the grip from racing slicks is a combination of adhesive (surface energy) and cohesive bond strength within the tyre compound, there is no chemical reaction taking place. There is also a mechanical aspect to the grip, whereby the tyre deforms over the surface of the asphalt, relying on the compound cohesion to transmit the traction.

The difffernt tyre compounds are designed to 'switch on' or 'melt' at different temperatures.

It's not that things shouldn't be challenged. It's just that there's an immense amount of BS floating around out there. The ratio of misinformation and speculation to fact is quite high.

Mikey's recent post on the other hand has some good points to it.

Thanks to Hail for this link ...

[youtube]http://www.youtube.com/watch?v=ykU8M2-h5Jk[/youtube]

Mr.G wrote:Due to the temperatures - there are only three boxes, it should be some info abut pre heat or something like that. If it sholud be for the whole sting the template should have more rows like we see before.

I would think the three boxes would be something more like: Left shoulder, center, right shoulder.

Jersey Tom wrote:It's not that things shouldn't be challenged. It's just that there's an immense amount of BS floating around out there. The ratio of misinformation and speculation to fact is quite high.

Mikey's recent post on the other hand has some good points to it.

Kind of ironic when you disagree with me that harder tyres require more heat to work efficiently or that heating the tyres changes the characteristics of the contact area, then go on to say Mikey has good points when they align with mine.

JT - thanks for putting in your tyre expertise on this matter. If you had a tyre with the same rubber "thickness," same construction, basically identical in every facet, except for the hardness/softness of the compound - would they (generally speaking) have a similar working temp window, or would they be operating in their own windows?