"Working" tyres hard

[Jersey Tom]

How would you be able to tell either way? IR sensors aren't particularly good for this sort of thing... the trend you see in IR can be opposite of the actual tread temperature.

not when you are at the lower limit of the window

Not sure what you mean by this.

[WhiteBlue]

How would you be able to tell either way? IR sensors aren't particularly good for this sort of thing... the trend you see in IR can be opposite of the actual tread temperature.

not when you are at the lower limit of the window

Not sure what you mean by this.

Bridgestone give a low pressure limit in their specification. Some teems routinely ignore that to a certain degree but you are on your own if the --- hits the fan. So if you already run at the low end of the window lowering tyre pressure isn't an alternative.

[Jersey Tom]

Regardless, when it comes to discussions regarding tire heat and grip, everything gets very hand-wavy very quickly, with little hard data to back it up.

[DaveW]

If you want your tires to run hot, take air out. Done.

I could rabbit on about this topic. But I have done so in previous threads, so I will refrain for now.

I agree with JT's contributions here, including the above quote. However it is a widely held opinion throughout the pit lanes of the world that increasing tyre pressures is a way of bringing the tyres up to temperature quickly. Any idea why?

[marcush.]

If you want your tires to run hot, take air out. Done.

I could rabbit on about this topic. But I have done so in previous threads, so I will refrain for now.

I agree with JT's contributions here, including the above quote. However it is a widely held opinion throughout the pit lanes of the world that increasing tyre pressures is a way of bringing the tyres up to temperature quickly. Any idea why?

starting with increased tyre pressure will lead very soon to a decreasing size of the contact patch ,so the ultimate grip is less leeading to mor wheelspin or slidíng which creates surface heat.that is my idea of it.

[DaveW]

starting with increased tyre pressure will lead very soon to a decreasing size of the contact patch ,so the ultimate grip is less leeading to mor wheelspin or slidíng which creates surface heat.that is my idea of it.

OK. Makes sense, but does it stack up with the fact that, in some race series, anyway, "cold" tyre pressures are apparently set higher for qualifying than they are for a race?

[DaveKillens]

Hey all.

This is a topic that's been bugging me since it's been widely established that the BGP001 works the tyres very lightly. How is it possible that they have all that downforce, and yet it works its tyres very lightly. The Red Bull had less downforce than them, and yet worked the tyres much harder!?

What other factors are actually involved in tyre wear? Thanks!!

A racing tire, especially slicks, generate heat by slipping, sliding, and distorting the carcass. But when you increase the downforce, and this makes it more difficult for the tire to slip and slide.

So if you had two identical cars, but one with less downforce, it would generate more heat in the tires as it attempted to keep pace with the car with higher downforce. Eventually the tires would degrade from the excess heat, and the lower downforce car would most likely have to pit for new tires ..... while the car with higher downforce just keeps on going...

As far as setting the tire pressures higher on qualifying, it must be remembered that the qualifying tire is expected to achieve optimal temperature after the out-lap. In other words, the car exits the pits, does one lap, one qualifying lap, then it's over. With higher tire pressures, the tires slide more, heat up quicker, and are hot enough for that qualifying lap.

For race trim, you want the tires to survive much longer, so you run lower pressures than qualifying so that the tires heat up more gradually, and last more than just one or two laps.

[F1_eng]

Do you seriously think that the world's best race engineers haven't thought of lowering the pressure as their answer to the problem. I can see it now:
"Hey Jock, just let some air out!"
"WOW, thanks a lot for that, so clever, why didn't we think of that?"

The more you lower the pressures, the more roll will occur. Tyres account for more roll on the cars than suspension travel does. Not to mention a complete change to transient response. You would begin to ride along the plank very soon if you dropped the pressures, so you say raise the ride height which further increases roll, you quickly start chasing your tail.
An example of how setting un-desirable pressures: you set the pressures too high so the contact patch is smaller than usual, the car understeers badly which generates a lot of heat in the tyres which raises the pressures, which raises the ride height and further increase the load transfer which causes the understeer to get even worse.

marcush, the more you deform the tyre, the more heat is generated through a shear mode on the rubber. For example when you bend a flat piece of bar quickly, you can feel the heat generated.

People should read more about a topic before posting silly things, dismissing topics purely because they don't understand them is not clever. I am refering to the comment about lowering the tyre pressures. Hans Pacejka has written a great book about tyres.
It really annoys me, these people that think because their mate has a track car and he can lower the pressures to improve grip. He probably can because it was so awful in the first instance. Formula 1 cars are on the edge in every possible was, so any slight change to anything could be disasterous.

[DaveW]

DaveK - Thanks for that very logical explanation. My small mind has a problem with it, however. Why can't a driver when qualifying force lower pressured tyres to slip & slide during his out lap, replicating what would happen with higher pressured tyres?

[Jersey Tom]

Do you seriously think that the world's best race engineers haven't thought of lowering the pressure as their answer to the problem. I can see it now:
"Hey Jock, just let some air out!"
"WOW, thanks a lot for that, so clever, why didn't we think of that?"

The more you lower the pressures, the more roll will occur. Tyres account for more roll on the cars than suspension travel does. Not to mention a complete change to transient response. You would begin to ride along the plank very soon if you dropped the pressures, so you say raise the ride height which further increases roll, you quickly start chasing your tail.
An example of how setting un-desirable pressures: you set the pressures too high so the contact patch is smaller than usual, the car understeers badly which generates a lot of heat in the tyres which raises the pressures, which raises the ride height and further increase the load transfer which causes the understeer to get even worse.

That is exactly my point in that it isn't just heat that's the issue, otherwise it WOULD be a simple solution.

[DaveW]

F1_Eng - The opening remarks in your last post are, perhaps (or perhaps not), more entertaining than you realise.... The less said about your last two paragraphs the better, I think.

You might, however, have a point for aero vehicles. Increased pressures will lead to a higher c.g. position at any airspeed & will cause more load to be transferred to the loaded tyres in manoeuvres. I guess that would heat tyres more quickly, although intuition makes me think that the effect would be relatively small...

Alternatively, the increased stiffness of higher "cold" pressures might encourage a driver to "lean" on them more during his out lap. That is my current favoured explanation for using higher pressures during qualifying. The strategy won't (or is less likely to) work for a race, because crowning at elevated stable pressures will reduce grip.

[F1_eng]

More entertaining than I realise?

"You might however have a point" Thank you your grace! Don't patronize me, and stop guessing answers, get some books or some track data.

You say that for qualifying, higher pressure will heat the tyre quicker then you say during the race the higher pressure would reduce grip? Grip is even more paramount for setting the best single lap time.

I give up, you're making it up as you go along.

[WhiteBlue]

Producing the desired tyre utilization characteristic has been difficult even for the most experienced teams with competent engineers. Ferrari went wrong in 2005 and suffered a dismal season. Toyota got themselves a highly paid specialist who had done vehicle dynamics for Michelin and Renault (Vasselon) and struggled several years to come to grips with the problem. The fact that Brawn with 18 years of experience in the business had the same problem last year simply shows that it definitely is not trivial.

Obviously the aerodynamic front and rear concepts with the resulting aero loads, the native weight distribution before ballast and the amount of ballast available together with the suspension design and the tyre characteristics play a role. It must be a mother of a problem when things get out of hand.

[Jersey Tom]

I give up, you're making it up as you go along.

Welcome to motorsport A blend of fact, fiction, and questionable interpretation... at every level. F1, pro, amateur, you name it.

[Belatti]

Ill quote Mystery Steve signature here

"...engineering is the art of moulding materials we do not wholly understand into shapes that we cannot precisely analyse, so as to withstand forces we cannot really assess, in such a way that the community at large has no reason to suspect the extent of our ignorance."

In the case of tyres, the underlined part is not that precise