tyre temperature - the only thing that matters

[DaveW]

WhiteBlue - Grooved tyres could be used to adjust grip levels, but not tyre stiffness, not significantly, anyway. I understand that Bridgestone believes that current problems arose because the relative contact patch area gain resulting from the change to slicks was greater at the front than the rear. That might well be a factor. However, teams had problems before slicks were introduced, & if contact patch area had been the sole problem, it is hard to believe that a solution could not have been found by adjusting cambers & tyre pressures.

I also understand that Bridgestone has proposed that the front tyre size (presumably width) be reduced for 2010. That would probably reduce vertical stiffness by itself, but they might also take the opportunity to further reduce stiffness with a construction change. That could be entertaining if my thesis is correct (especially given the current aero regulations), because teams would then have the opportunity to engineer themselves out of their current "corner".

The situation with KERS is interesting, because it is useless until acceleration becomes power limited (unless, of course, it is used for traction control - but that wouldn't happen, would it?). The earlier it can be used when exiting low speed corners, the more effect it will have on lap time. Hence traction is important. Traction, for an F1 vehicle, would by improved by a) moving the centre of gravity aft, b) moving the centre of pressure aft & c) controlling rear contact patch load variations more effectively. My thesis would suggest that the first two might be improved by reducing front tyre stiffness, but all three could be improved by increasing rear tyre stiffness. The fact that a GP2 rear tyre (for example) has a vertical stiffness that is higher by the equivalent of around 10 psi suggests that such a change would be feasible.

[WhiteBlue]

Tyre rules are very critical and they must be set very early ahead of the season. I believe that next years cars will be substantially different due to the ban of refuelling. The average weight and the weight differences will be much higher. It could also have an impact on weight distribution? So perhaps they should take that into consideration when they look into different tyre formats. It could also be a good idea to have Bridgestone prepare two different constructions which would be evaluated by the teams and one chossen during winter testing.

[DaveW]

The next six months is likely to be interesting, both on & off track.

[marcush.]

isn´t it bizarre that no team really has taken into acount the possibility of having hot conditions in some races and cold in others?
May it be simply suspension geometry,damper philosophy,or aeroeficiecy more temp related on some cars
I bet Brawn ,Neway,Willis,Simmonds etc all know the root course why they are quick in certain conditons and why the monster does not work in all conditions.
Obviously RB and Brawn have no little to no overlap in optimum working window with no temp in your tyre theres no way to get grip.Interestingly with no grip the car should slide a lot which should give temps?
So it is the way you generate the heat which is determining if you are only graining the tyres or raise the grip level...
Honestly speaking this is not a driver thing ,I must believe that someone making it up to F1 does know how to push.
Sure JB knows that weaving on the straights will definitely not bring any meaningful temp rise but of course it will help to get rid of the marbles and avoid collecting too much pickup..
I could imagine rb is doing something with the tyres in terms of track variation in bump(as an example) whereas Brawn isn´t .I also asume this is a front tyre thing getting rears up is
unlikely to be a problem but of ourse with the fronts stone cold you will need to abuse the rears to balance the car so this will end in trouble front and rear...
so yes ,tyre temp is all that matters but the key is to understand and properly analyse whats going on.

I assume you need at least two different front suspension layouts/concepts depending on track/ambient temps and of course track surface.

[BreezyRacer]

For what it's worth RB changed the weight distribution via wheelbase with the big redesign at Silverstone. Should the need arise I imagine they can always adjust the parts back and forth.

I've studied the changes of the McLaren in Germany too, and they also look to have shifted the axles back a little too. I cannot confirm that however, it just looks like it .. maybe 40 mm or so.

Any team can also add "scrub" in the form of toe settings to build heat too, and to some degree camber, but camber is tricky. The best of all worlds is to not have to do any of these things.

One last thing .. I bet that when we get to a hot race Red Bull kick ass again. This whole "cold tire, hot tire" thing is just a ruse. The Brawn is a draggy car. That made it great when it was the only high downforce car on the track but now RB does that without all the drag. I would expect that at the next race you will see a Brawn with splitter revisions and possibly new sidepod inlets, all in an effort to get rid of drag. Can you imagine how slow Brawn will be at Monza if they don't address this issue? If you don't know what I'm talking about just look over the straight trap speeds. They be very slow ..

[ISLAMATRON]

trap speeds have been very deceptive this year... check this thread

viewtopic.php?f=1&t=6693

[Racer_D]

This is a mighty interesting topic I've stumbled upon!

I happen to have a few questions on tire temperatures - but they are more related to temperature distribution.
In one NASCAR-related blog, a crew chief said that the aim is to have the surface of the tire equally heated, so I,M,O temps the same. So they adjust camber until this point is reached.
In another NASCAR-article, it was said that a 'good' distribution is Inner the highest (optimum being about 220F), and the rest is about 15F apart.

Now I sometimes have the pleasure to watch a test of FRenaults or Formula 3s at Zandvoort. When I look over the shoulder of some of the engineers, I see their tire temperature distribution also highly unequal. I,M,O are 4 to 6 deg C apart.

What is 'good'? Maybe it makes sense to have tire temp distribution the same, as it is the same rubber and thus the same optimum operating temperature. However, I would imagine that the load on the tire is not distributed evenly over the contact patch?

At the same time, Camber in itself yields side forces (more camber, the more a tire will generate a force towards the camber angle which can aid in the car's balance). So maybe these camber-related tire forces are more important than an even temperature distribution?

Who knows something about this?

[Jersey Tom]

In one NASCAR-related blog, a crew chief said that the aim is to have the surface of the tire equally heated, so I,M,O temps the same. So they adjust camber until this point is reached.
In another NASCAR-article, it was said that a 'good' distribution is Inner the highest (optimum being about 220F), and the rest is about 15F apart.

They can both be right, at the same time.

Hint: Depends how they're measuring it.

I'll also say those NASCAR guys aren't telling you one of the more critical aspects of setting temp spread. Not gonna say what it is though.

[Racer_D]

I'll also say those NASCAR guys aren't telling you one of the more critical aspects of setting temp spread. Not gonna say what it is though.

Well that's intriguing
What do I have to do to make you say it? Or why not say it in the first place?

[Jersey Tom]

I'll also say those NASCAR guys aren't telling you one of the more critical aspects of setting temp spread. Not gonna say what it is though.

Well that's intriguing
What do I have to do to make you say it? Or why not say it in the first place?

If you were an engineer or technician in the series, I'd tell you. Or you'd already know, I guess.

In any event, if a raceteam is building their setup purely around pyrometer temps on pit-in, they're leaving heaps of performance and speed on the table. So to debate whats "optimum" (hate that word, nothing nothing nothing is optimum) in that regard is a little silly IMO.

[Racer_D]

So to debate whats "optimum" (hate that word, nothing nothing nothing is optimum) in that regard is a little silly IMO

Well - call me silly, but a tire needs to stick? So optimum temperature would be the one where it sticks most? Now, perhaps there is an optimum temperature for tire load, because each different normal load will cause a tire to stick differently?
But can you say there's an optimal temperature for 'stickiness' or grip for a given load N?

You leave me guessing for the stuff you aren't telling. What's the desired effect of temperature spread? Wear?

Or the fact that if you distribute heat as a 'bandwidth' across your tire, at some point on the patch there is an optimum?

[marcush.]

If you did ever see a tyre temp graph during a lap and then back into the pits ,you surely would follow up JTs words.
We already concluded theres´no absolute optimum temp because simply this is not going to be constant ,all you do is look at the averages really.
So if the tyre on pit in averages at say 90°C inside,middle outside you cannot hope it did so in the corners as well ,with all the forces acting on the tyre...So maybe you got way too high temps on the outer edges ,or not a good spread of temps on the straights due to underinflation with downforce but all this you may or may not see when the car is coming back into the pits.
What you will definitely see is signs of abuse of the tyre if you take a close look at the TYRE !

[Jersey Tom]

Well - call me silly, but a tire needs to stick? So optimum temperature would be the one where it sticks most?

Only partially right. As I'm fond of pointing out, more grip does NOT always = faster lap time.

Plus, heat is generally bad for rubber. Let's say that running the tires hot does indeed give you a lot of stick. Running it really hot may make it fast and then fall off like a brick. Maybe keeping it cooler, not as fast on one lap but longer on a stint.

Quantifying that kind of thing is... tough or impossible.

I'll let you marinate on that for a while.

[Racer_D]

If you did ever see a tyre temp graph during a lap and then back into the pits ,you surely would follow up JTs words.
We already concluded theres´no absolute optimum temp because simply this is not going to be constant ,all you do is look at the averages really.

Okay, that's clear. I haven't seen a real tyre temp graph. But my question then is: suppose I have tyre temp logging on a race car, would I be aiming for a nice even surface distribution *in the corner*?
Is the NASCAR-crew chief aiming for nice even distribution when he is running on a superspeedway (no braking, constant 100% throttle, small steering angles)?

2nd question then: If the race engineer of a single seater (F3, FRenault) is checking tyre temps in the pits (assuming that the driver kept pushing reasonably on his in-lap, as drivers should do), what is he looking at then? He is checking Inner, Middle, Outer temperature, and these are *never* equal.
Should they be equal? Is he thinking, okay, if these temperatures are 5 deg C apart, and the Inner is highest with 90C, that's reasonable? I.e. can he relate the temperatures in the pits to what's happening on track? And if it's not 5C apart after a certain stint, but 3C, does he have more info to use in his analysis? And if so, what does this differential tell him?

[Jersey Tom]

There are different schools of thought on tire temps and setups. Some people swear by pyrometer. Some swear by IR from DAQ (though surface temp does not tell you how the depth of the tread is working).

IMO if you're only looking at pyrometer temperatures for setup, you're leaving a heap of performance on the table.

Some tires at some tracks may want a different temp spread than others. There's no one answer for what is best. That's another reason I say the concept of "optimum" in racing is BS.

Everyone has their own tricks of what to look at, when, and in what light.