How can teams resolve tyre issues?

[DaveW]

You are right there ...with only one set of option tire there is not really much scope for experimenting and no chance to have real back to back testing....apart from a split between your two drivers ....

thinking of it it is more of a wonder that teams do not drop the ball more often...

Fewer tyres = supplier can/will pay more to FIA/FOM for the contract. Obvious, really. Note: no rig tyres (explicitly), but "scale" W/T tyres a requirement. Significant, perhaps. Small wonder some teams are "lost".

[marcush.]

so the teams get their total tyre allocation at the start of the weekend, and choose wich ones they use for FP1-3 and which ones for qualy and race?

[747heavy]

some of you may find this video interesting.
Enjoy:

[youtube]http://www.youtube.com/watch?v=pFijucD1 ... re=related[/youtube]

[747heavy]

some of you may like to read here a bit, it covers aspects of the dynamic glass transition in tires.

http://books.google.com/books?id=8p425F ... &q&f=false


Reading a bit about it, over the last couple of days, and trying to link it to the original question of this thread, it seems that teams may need to consider the "preparation" of there tires.
As we have mentioned in detail in this thread, teams are in a conundrum, the ultimate answer lays in a car, who´s characteristic is best suited for the given tire.
Without a.) valid and detailed tire data for use in simulations or b.) the option to test tires either on tack or an rig, it will be difficult to find the answers needed, to solve the problem.
If design parameters such as aero balance &/or weight distribution can´t be adjusted/optimized in the nesessary direction, gains may be made by experimenting, with different setups (spring/damper/inerter) to generate energy/frequency inputs into the tire, which either generate "desired" input´s or counter existing "undesired" frequencies allready present.

This thinking goes along the lines of the TMD setups, and revolves around not only the frequency but also the phase angle and amplitudes of the different frequencies. There could be ways, similar to techniqes used in accoustics, to cancel out frequencies, by generating the same frequency with a 180° phase shift, as used in noise cancelation headphones etc.

On the other hand, tires seem to react different in tems of graining, duration and warm up/head built characterestics if we compare new(sticker) vs. scrubed in tires.
Maybe some teams can find gains in race pace, by carefully scrubbing in there tires, before use,and use different pressure settings
As allways, there are tradeoffs, in terms of one lap performance vs. race distance performance. I think DaveW has given some good examples.

Another example out of my expirience is, that if you set your pressure slightly lower (1-2 psi) for a new tire, you get a tire peak for qualifying which lasts for about 3 laps. If you start with a higher pressure, the peak becomes a little bit higher but much narrower. For this given car/tire/track example if you choose to start with slightly higher pressure, it was worth around 0.1sec in laptime, but you have only one lap. If you manage it well, and your driver can pull it off, you have this gain. If you commit to this setup/pressure and have traffic or a mistake in this lap, your next lap will be 0.2-0.3 sec slower, where with the slightly lower starting pressure, you have a performance plateau of 3-4 laps, where you can get the same time. It´s not allways a easy decision.

Some questions which I still have in my mind.

Is there an "optimum" frequency/amplitude to warm a tire ???
Thinking something like resonance frequency of the molecules etc.???
As we have talked about, there are frequecies at which the rubber will not be able
to relax completely again, therefore loosing "mechanical grip" from interlock with the track texture, leading to a reduction in grip.
Can we (try) to manipulate these frequencies, and if how??
It seems that over Tg the stiffness of the rubber remains app. constant for a temperature range, based on this graph.




Is this true/ can you see this on the rig DaveW ???

Thanks

[timbo]

I strongly believe that F1 tyre never comes close to glass transition.

[Jersey Tom]

You are not going to produce a polymer dynamic stiffness chart on a 7-post.

Nor should you even bother thinking about it, IMO. Unless you're a tire designer.

Vast majority of engineers probably have enough difficulty really knowing what the most important parts of a Fy/SA or Mx/Fy chart mean. Much less anything else. Don't jump off the deep end.

[747heavy]

thanks for your opinion Tom - much apriciated

[marcush.]

so back to square 1 and try empirically to get the best out of the black stuff??

[DaveW]

Apologies, 747, I don't think I can contribute much to your question. I did find your explanation of high pressure vs low pressure performance very interesting, however.

so back to square 1 and try empirically to get the best out of the black stuff??

That sums it up nicely, I think. From my (very one eyed) perspective, the front & rear tyres have a very similar vertical stiffness (sorry folks). The suspension set-up means that the rear tyres will be over-worked relative to the front tyres unless they (mis)use a front inerter. The remaining option is to move the c.g./c.p. (I assume they move together).

My crude rule of thumb suggests that the c.g. should be close to the geometric centre of the vehicle. The problem is moving the c.g. forward removes weight (& down force) from the rear axle, which will "cost" traction. The best compromise is likely to be track-dependent &, without good tyre models, can only be determined experimentally.

Adding an over-sized inerter to the front axle will certainly help to work the tyres, but will "cost" front grip over the course of a race. Yet another variable to be added to the "cost function"....

[marcush.]

I thought the relationship with pressures was clear ...but have to admit my pressure adaptions were more like 0.1bar than 1 or two pounds..But in my kind of racing it was always hard to enforce the mechanics to ONLY use my pressure gage ..as it was calibrated.. and only available for MY driver...(the best weekend was when I found out our team had 4 seemingly identical gages in the pits ALL with different readings for the same pressure on one tyre.. that convinced the boys to at least only the same gage every time.. I will not tell the name of the team ,don´t worry ).

HAHA ..i just started to think again and calculate..0.1bar Is indeed 1.4psi ..so we matched ... funny .
I have to admit I never worked with psi ,so please forgive me for being THAT ignorant..

[747heavy]

No apologies needed Dave - thanks for your input - it´s valueable.
Thanks for a interesting & enjoyable conversation gentleman.
We may have not solved the riddle, but I think we have put some interesting
thoughts forward, and have now new "fodder" for thought.

@Marcus - sorry is a bit off-topic
I come out of the "metric" world , and have used >bar< for the first 10 years of my career.
But over the years I found that many teams, especially in circuit racing
use PSI for tire pressures, even if they use N/mm for springs etc, and bar for
fuel or oil pressure.

One old race engineer, has given me the following explaination.
I´m not sure if it´s true, but for me it makes some sense.

In most mechanics/people mind a 1-2 unit change is perceived as "meaningful" , where 0.1 unit is maybe seen as "well this can´t be that important".

He said, it´s easier to get mechanics to follow a 1 or 2 psi change, and do it consistently then to get them to make a 0,15 bar adjustment.
Keep in mind that a lot of his expirience pre-dates the digital tire pressure gauge
era as well.
Maybe there is something in it - I don´t know, but for me it makes some sense.
Especially in lower forms of motorsport, where the tire guy/mechanic is not that expirienced, and don´t know all the implications of pressure changes.


Your example with the tyre pressure gauge, is more common, then you would like to believe.
Also of interest, given the importance of tire pressures, is the observation that some teams spend thousends of dollars on dampers, and other parts, but sometimes(often) use a 5$ pressure gauge from the Supermarket, or a give-away from a supplier.
Not all go and check against the gauges used by their tire supplier, to make sure you talk about the same pressure, when you say xx psi/bar.

[DaveW]

I had the same (pressure unit) explanation first hand from an Italian race team. Ultimately, it's just numbers.

I also know of a team that doctored gauges to keep the tyre tech. happy (FNippon/Bridgestone). Allowed them to run higher rear pressures.

[747heavy]

nice anecdote Dave - thanks for sharing
Thought the opposite case would be more common.

courtesy to "autosport.com" what Massa has to say about his/the tire woes:

>>> Speaking about the tyre issues, he said: "I think in the races where we had the very hard tyres I was performing much worse than I can because I was never able to make the tyres work. But when we had the soft tyres I was okay.

"I've tried to change my driving style, to make the tyres hotter and better. I am a driver who needs a lot the front grip of the car. I prefer better front grip and even when you have a bit of oversteer you can work to improve the rear.

"That is how I drove up until now. But this year with hard tyres it is very difficult. Lots of people talk only about me, but many, many drivers have the same problem." <<<

[marcush.]

747heavy ...believe it or not ,in 2007 ,I had the pleasure to have free Goodrich (Michelin) tyre supply in VLN with a really not important team...On the first race ,I did my usual thing went to the tire guys and compared my gage and temp.probe with theirs.And guess what ? the two nice blokes had a huge grin on their face directing me in their office for a nice chat..explaining they had waited for years already to
experience a teammember checking for correlation of equipment....I will not tell you which teams also ran Michelins that year...makes you think twice... also it was complete new to them to get complete running sheets of every tire we used or did not use ,number of laps ,times, pressure and temp history ,you name it.I was amazed to learn the Pro teams with their expensive machinery were abusing their tyre supplier by not giving ANY feedback ... .

[DaveW]

Thought the opposite case would be more common.

I presume you refer to tyre pressures. I did say my view was one eyed... Actually, when rear tyre rates are too low, increasing rear pressures will improve rear CPL control. This at the expense of rear contact patch area. One helps, the other hurts. A track test will determine which is the more important. (Note: increasing rear pressure might allow reduced camber settings, which will further increase tyre rates & may recover contact patch area. Increased pressures should also increase lateral stiffness, which the driver would probably appreciate).

I am fairly sure that PM was talking about his front tyres. I think FA's driving style means that he would be less affected, & could encourage the team to adopt a more rearward c.g.

JB seemed to have similar problems in the second half of last year, when I think the under-steer caused him to destroy his rear tyres (hence under-steer followed by over-steer, with nothing in between). It was the habit of at least one F1 team to increase traction by running reduced rear pressures (in the days when tyres were sensible). In my view, that solution would only make the current tyres worse. I sometimes wonder if old habits die hard....