How can teams resolve tyre issues?

[747heavy]

PART 2 - get your toothbrush ready

"What is a tire anyway?" , "What is a green track?", "What is graining?", "Are tire engineers/techs lying to their customers?" "Why heat/temperature is important"



So, let´s continue our little story about tires, F1 and life in general.
To come closer to the answer of the question, what can teams do in this situation and which challenges they face,we need to understand a little bit more about our tires, and how they work on the car.

Yesterday, we have covered some basics, about how a tire generates grip, and which factors
have an influence on the amount of grip available.
We have seen that component 3 (intermolecular bonding/chemical grip), is very powerful.
What has this to do with our tire on the car/track ???

As we have seen in our experiment in step 2 yesterday (when we moved the rubber over the grinding paper), small amounts of rubber get deposited on the other surface.
For the tire, that is the track. So during a race/weekend we deposit more and more rubber on the track/racing line. That makes component 3 (chemical grip) become stronger and stronger. So the overall griplevel increases.
Some people call this effect "the track rubbers in" or "painting the track", "laying rubber down".

So what is a "green track" ??

Green track is a reference to a track, with very little or now rubber down. This is usally the case during FP1 and is more pronouced on tracks with little or no racing - street circuits like Monaco for example.

This explains while the teams try to run as late as possible in qualifying, as the track normally get´s faster and faster, and the last car has the best track conditions.
But this approach, can nicely backfire, when you wait for the last possible minute, and somebody blows up an engine, it starts to rain or you get a yellow/red flag on your lap.
If you have not put in a "Banker lap" earlier, then all your great strategy and gamemanship goes out the window.
In extreme cases you go out in Q1 or qualify for the last row - maybe with a very quick (pole) car.
It´s easy to look like an idiot in this situation. (Been there, done that )

It also explains why the big (good) teams, don´t run much in FP1, because for them, their is not much to learn. The track conditions/grip level is too far away from where it will be in the race or in qualifying.
It´s better now with the limits in track testing otherwise, they maybe would not run at all in FP1.
They may run some checks, make sure you don´t have a oil/water leak and all the sensors and systems are working, calibrate some sensors etc. This is what they call installation laps
You can´t really start working on fine tuning your setup under these conditions, as you risk to work in the wrong direction. (we will later see why)

Now, what is this intermolecular bonding/chemical grip thing? How does this work?
What has this to do with temperature?
Here it starts to get difficult (for me). I will try to explain it as easy and straight forward as I can. I´m sure it will make some(many) people laugh, but it´s the best/easiest way I could come up with. Maybe Tom or any other real tire expert, can add a little bit more to it.

Let´s start simple. It´s a chemical process, where the rubber molecules of the tire form a
temporary bond with the rubber molecules on the track. As it is a chemical process, temperature is important. (Like when you try to glue two things together, if it is too cold your glue will not work, you need a minimum temperature for the chemical reaction to work)

Imagine (for the purpose of illustration), your rubber molecules as small balls with 6 arms/hands each. The balls are hold in place in a rigid grid/array (at first).
So the molecules in our tire will shake hand with our rubber molecules on the track. For a brief moment, they shake/hold hands forming a temporary bond. As the tire moves over the surface, bonds are made and other bonds break, because the hands move out of reach and others come into reach. At any one time, their is only a limited amount of bonds possible.

Now, if our grid/array which holds our balls in place, is flexible instead of rigid, the balls can move a bit, and therefore reach more hands and make more bonds with other balls/molecules.
So at any one time, we have now a higher number of bonds/hands holding each other in place.

more holding hands = stronger bond(like better glue) = more grip.

And this is basicly the effect of the temperature in the tyre. It enables the molecules to move more freely, and to form more/stronger bonds with the other molecules.
This holds true for the bonds between the rubber molecules inside the tyre(across the tire) as well as between the rubber molecules of the tire and the rubber molecules on the track.
If the temperature gets to high, our grid/array becomes a bit of a mess, and our molecules go where they want to go, reducing the number of bonds = grip.
So again optimum temperature is key.

It is important to keep the optimum temperature across/through the whole tire.
We will see why, when we look at "graining".

So - it´s a good time for a coffee and a small break.
I hope when I´m back, some of you have stopped laughing, and started breathing again

to be continued soon ...............

[DaveW]

Good stuff, 747.

I am particularly interested in your views on the compromises between "chemical" (temperature related) & "mechanical" (contact patch load related) grip. Also on lateral balance issues: moving the c.g. & c.p. forward will "work" the front tyres more but will "cost" traction & will increase initial understeer. What to do if the rears "go off" before the fronts start to "work" (appeared to be JB's problem in the second half of last season).

Also why do heated tyres still require to be "worked" on-track? (I think I know the answer to that, but your thoughts would be appreciated.)

[Jersey Tom]

Not sure I'd agree that temperature mainly impacts "chemical" grip.

[ubrben]

Incoming from another tyre "expert"..

First off I'll throw the cat amongst the pigeons: There are some rubber polymer scientists in and outside tyre makers who don't believe adhesion is a significant factor in rubber friction other than on very clean smooth surfaces - i.e. not race tracks. I'm probably not one of those people, but I have my moments. That should make it clear that this is not a clearly defined field in many ways

I'd just like to put together a number of points to address some of the discussion on this thread.

1. The team bitching about tyres is invariably not winning, or going worse than it did recently. Defining the contribution of tyres vs. aero vs. engine vs. damping etc is very hard as JT has pointed out
2. F1 is so aero-biased that unless you have good aero you're nowhere it would seem.
3. I firmly believe that an F1 team with a crap aero package should cut their losses and develop the next car, or focus on mechanical setup. Modern F1 aero packages and the mechanical setups used to make the aero work (key point this - I'm sure DaveW can support this point) are not what the tyre necessarily wants. This is probably the hardest area for F1 people to appreciate. However if you compare the Q times of the new F1 teams, vs. the GP2 teams at Monaco (where engine power doesn't skew the results) you'll realise that there's some validity to it.
4. The only parameters you can truly specify to a first order on the car from tyre data are the long CG position and the long CP position - for this you need good force and moment data at different loads, cambers, pressures, etc. If you have this data you can define a good mech setup I've been involved in doing this and it works, but the data needs to be damn good.
5. If the other teams are ok (seems to be?) then Mercedes either have a screwy aero package, bad VD simulation tools for determining CG, a combination of both, or a generally crap car. In this case it's always easier to blame the tyres - believe me I know. But a tyre in reality doesn't have a fixed set of properties independent of the car and the setup determining the conditions under which it operates.
6. That brings me to a final point about tyre data - there is no way (even with rigs like Calspan) to fully assess the affect of compound properties and how they interact with dampers and track surfaces. This is why specific data isn't available to the F1 teams, let alone the public on a forum like this. The only way I can understand the compounds I'm working with is to go to a race track and test them.

A lot of people are talking about the quality of Bridgestone's tyre data. Fundamentally I would echo the people who've commented on the commercial aspects of this. Force and Moment data is not relevant for tyre safety and is expensive to measure. Therefore in a one-brand tyre situation only the bare minimum data will be supplied for simple economic reasons.

If you don't like a lack of tyre data or teams not having tyres suited to their cars you need to be in favour of open tyre competition or just suck it up.

As a final aside I'd like to point out that the most capable people involved in racing with the most practical experience who post on this type of BB tend to be in the lower range in terms of being certain of their position. People who come to their knowledge of aero, tyres, etc from books and magazines tend to be more certain. As with most things the more you know, the more you realise you don't know. It's not a criticism of anyone, or an attempt to polish my ego or Tom's for that matter. It's just an observation...

Ben

[timbo]

If the other teams are ok (seems to be?) then Mercedes either have a screwy aero package, bad VD simulation tools for determining CG, a combination of both, or a generally crap car.

Mercedes seems to have a decent aero -- it is fast in Silverstone and Turkey (most aero-demanding tracks).

[ubrben]

Not sure I'd agree that temperature mainly impacts "chemical" grip.

Agreed, bulk tread temp probably has a bigger effect on cornering stiffness.

Incidentally that's a massive point, but probably doesn't sound like it.

Ben

[ubrben]

If the other teams are ok (seems to be?) then Mercedes either have a screwy aero package, bad VD simulation tools for determining CG, a combination of both, or a generally crap car.

Mercedes seems to have a decent aero -- it is fast in Silverstone and Turkey (most aero-demanding tracks).

So the aero's good on two aero dominated tracks... That means one of two things is likely:

1. The mechanical package is crap and could be improved
2. They know the mechanical package is crap and know how to improve it, but a characteristic of the aero doesn't allow them to run springs and/or dampers that could improve mechanical grip without screwing the aero package.

I have a nasty and strong suspicion that mechanical setups of F1 cars are terrible and the teams focus 90% of their effort on aero. If you get it right you win, if you get it wrong you get beaten round Monaco by a GP2 car

Ben

[JohnsonsEvilTwin]

1. The mechanical package is crap and could be improved

Ben

How?
Thanks in advance.

[DaveW]

Good dose of common sense, Ben.... but I would like to see 747 complete his treatise.

I have a nasty and strong suspicion that mechanical setups of F1 cars are terrible and the teams focus 90% of their effort on aero. If you get it right you win, if you get it wrong you get beaten round Monaco by a GP2 car

Only 90%? I wonder what would happen if F1 & GP2 swapped tyres.... Now that would be interesting.

[Jersey Tom]

1. The mechanical package is crap and could be improved

Ben

How?
Thanks in advance.

We've been over this. Different springs.. different bars.. different shocks.. camber.. air inflation.. caster.. static toe.. Ackermann...

[JohnsonsEvilTwin]

1. The mechanical package is crap and could be improved

Ben

How?
Thanks in advance.

We've been over this. Different springs.. different bars.. different shocks.. camber.. air inflation.. caster.. static toe.. Ackermann...

JT

I'm looking for a magic bullet here!

[747heavy]

So now, we have got some people out of their reserve.
Thanks Ben,Tom and Dave for you contribution.
I´m fully aware, that the way I try to explain some things here, is very very simplified.
It´s a complex topic, and even within an expert group you hardly reach consens on all factors involved. I appologieze, if I have stated something incorect, and I´m glad that people like Tom and Ben come forward, to add to some comments or correct others.

Ben has summed it up pretty well IMHO. At the end of the day, it comes down to the best compromise. You can´t have it all. So you have to made some trade off. The trick is to know, where you can gain the most by loosing the least on the other end.
Aero is paramount in F1 so people tend to subordinate anything else. So all other things being equal, the car with the best aero efficiency (highest possible downforce, for the least amount of drag, for a given speed) will win at the end.

Now, there is a bit room for manouvering. If your aero configuartion is a bit draggy but your engine is a bit more powerful, you may get away with it and can take the fight to the other guy.
The same goes for the mechanical grip vs. aero compromise. If you lack a bit on the aero side but are strong on the mechanical grip side you will beat the guy who lacks on the aero side as well, but also lacks mechanical grip. But you will never beat the guy who is strong(er)/good in both.

There is only one optimum, and the car which represents the optimum, will win at the end. Other cars, may be on either side of the optimum and have their strengh and weaknesses
so they will come close(r) depending on track characteristics etc., but they will not be on top.

So, from my side, hats off to the design guys at RBR, I think they have produced a car, which at the moment, is damm close to the optimum. They are quick everywhere, even at Monaco, where aero does not account for everything.
Therefore it´s fair to assume, that they have a decent/good mechanical setup as well.
They just fall a bit short, in turning their car advantage into results (race wins/points)
at times.

To achieve this best compromise it´s not easy (otherwise everybody would win), and here expirience counts for a lot.
You can give all the tire data in the world to 10 different F1 designers, and they will not come back all with the same car. They will draw their individual conclusions from the data, and define different aereas as important.

It´s a very delicate balance, as Ben has pointed out correctly.

Sometimes you are forced to stick with a less then optimum solution, because you have a problem/deficit in another aerea. e.g. very pitch/ride height sensitive aero will pevent you from running a softer setup. So you will lose out on the mechanical grip, but if you help your mechanical grip you lose on the aero side. You painted yourself in a corner.

The other point worth noting is maybe, that optimum does not mean maximum at the same time.
You may have a car, which has the best aero, but in a very very small operation window. If you hit the window, nobody will come close, but if you are out, you lose a lot. So the other guy with a car which has less peak aero, but has a wider operation window, can´t beat you while you are in your window, but he will beat you the other time, when you are not, and he is. And he will be more often, because his window is wider.

Another variable which comes into play her is ego. And in racing circles it´s quite prominent, not just in drivers. I don´t know much about the inner workings of F1 teams, but
have spend many years in other race series with manufacturers and independent teams.
Depending of the culture and organizational structure of your team, different fractions have
more or less power/say in the overall design/setup process.

Let´s have a hypothetical meeting before we start our new car. We read the rules, gather all the data (including tires) we can get and sit down.

Let´s assume the Aerodepartment has 1st choice. The aero department leader will say, I want this this and this, for my aero package to work. Thereafter the engine guy says, sorry we can´t run radiators that small, it will affect my engine performance. Now, we either find a amiable compromise and try to find the best solution or one is told, that is how it´s going to be - deal with it. Then the suspension guy says, well can we make that gearbox/engine a little bit lighter/smaller then I get a better layout for my wishbones, and a better weight distribution. The engine, aero and g/box department heads look at him and say - NO - deal with it. At the end of the day, the Bridgstone guy thinks quietly to himself, it´s going to be a difficult year.

Sure this is pulled out of thin air, but I have been sitting in many meetings for hours and just listened to pro/con arguments from different fractions. In my case mainly engine vs. the rest of the car. I assume the pecking order in a F1 team is 1. aero 2. engine 3. the rest.

Sometimes the ego battles will stand in the way to better overall performance, just because one party did not want to compromise on one aspect.
I does happen, more often then one may want to believe.

[747heavy]

I'm looking for a magic bullet here!

Many do "Magic bullet" or "Holly grail"
As far as I know, they don´t exist.
It´s about common sense and compromise to achieve the best overall performance.
The physical laws are in place for everybody so no magic here.

There is this old saying I quite like.

"At the end, everybody is just cooking with water - but some people make the water cook quicker then others"

I think the best/smartest people in F1 (and in general) just make their water cook faster, then the rest of us.

[747heavy]

I don´t work for any tire company, and never have in the past, but would like to make a case here for them, and maybe help to get some understanding and sympathy for them and what they are doing and why they do it.

Markus has told us about his expirience with some tire techs, which would not comment on pressure/camber settings beside their recomendations. "Are tire techs/engineers lying to their customers?"

Let me take on my tire company hat to do so.

I do know my product, his strong points and his limitations/weaknesses.
I have a single tire contract with a race series, so I will supply a tire which is safe and up to the job. What means up to the job? It means a tire that will withstand most/all forces
and conditions it is going to encounter in this series. I don´t want the tires to fail in front of (in case of F1) millions of TV viewers aound the world.
Is this the best/fastest tire I can produce? No off course not. In a single tire supplier situation the tires are in general conservative/safe tires, which are a fair bit away from their limit. I want a large margin for error, or onforseen events, such as exessive track temperature etc. I´m sure Bridgstone could make a tire which is 1-2 sec quicker around any given track. But why should they do it.
At the end of the day one car will win with their tires so they will win as well.
The other teams will be unhappy, and some will blame the tires - their can be only one winner - nothing I can do against. I don´t need to defend myself, because the guy who won used the same tire, so the tire is not the problem in general.
So my upside is limited, one car will win on my tires anyway, some people will not and be unhappy - that´s life. Do I care if the laptime is 1 or 2 sec slower or faster? - No is the same for everyone. What about the downsides - they are there and they a great.
What do I don´t want to see? A camera shot which shows a car with a flat tyre limping back to the pits. A catastrophic tire failure(blow out). A crash caused by a tire failure.
What is my worse nightmare? In extreme (and I hope it will never happen), in case of an high aero car (F1, Indy or LMP) a car has a catastrophic tire failure gets airborne flies into the grandstands and kills x-people.

This happens once and my image is tarnished for years to come. All my carefull marketing and
promotion with this race series are out of the window. I may face prosecution as well.
Once is enough, nobody will care that we supplied tires for x years without problems.
So we will not push the limits in this situation, because we have much more to loose then to win.

So the recomendations they give, are aimed to provide good performance over a wide range of conditions with a good safety margin. They want you to get good performance from their product, and have little problems with it (in terms of catastrophic failures).
You stick to their recomendations, and you will be safe, but maybe never win, because somebody is playing the margins, and ventures outside this recomendations.
Will that make may car quicker? Sometimes it does, but it reduces the safety margin. You run
different pressures or more camber, most likely you go a bit quicker, but for how long, and if you blow a tire by pushing the limit what then?
Chances are, that you will blame it on the tire (company), very view will say in an post race interview, "We lost the championship, because we did not follow the recomendations of xxxx", most will say we lost because the f...... tire blow up.

Is there life outside the recomendations, yes their is, but don´t expect your tire guy to help you explore it. This is your job, not his.
He can´t win in this situation, and he will allways lose if it does not work out.
So have a bit symphaty for these guys out there, they have a difficult job.
And making you win, is not one their job, it´s yours

For similar reasons Intel/HP will not show you how to overclock the CPU in your computer,
or a car manufacturer will not help you to chip tune their engines. Does it mean it is impossible?
No - just that you are on your own if you want to do it.

So these guys don`t lie to you, but they don´t tell you everything they know either.
Because they don´t want you to go into the margins of their product.
They will not help you to abuse their tire, even if this makes your car go quicker under
some specific condition. Especially not in a single tire formula.

If you have a full on tire war, with exclusive supply deals, then they will help you to
really push the enevelope. They will make tires which are close to what is technical possible at the time, they will point out some aeras where you could optimize your car, to help there tires perform even better, or if this is not possible they will build a tire to complement the characteristics of your car. In a situation like this, you can learn alot about tires and what make them go quick.

On the other hand, as tires have such a great influence, you may find yourself on the "wrong" tire, and no playing around with setups or engine will help you to overcome a deficit of your tire at this time.

They become the most important factor, now when the tire is limited, the focus shifts to other areas to gain an advantage. As aero is the next best thing, this is where the money goes, and most of the effort is made to try to gain an advantage.
If tomorrow they indroduce a single aero package in F1, then the focus shifts to other areas such as mech.setup and other teams may gain the upper hand, if they have more expertise in this area then the others.

[Jersey Tom]

How?
Thanks in advance.

We've been over this. Different springs.. different bars.. different shocks.. camber.. air inflation.. caster.. static toe.. Ackermann...

JT

I'm looking for a magic bullet here!

"More camber."