Why are unused tyres scrapped?

[n smikle]

It's amazing to me that Pirelli has 200 slick tyres to scrap after FP2 at Silverstone today. Crazy.
Is there an expiry date on the tyres or something? I don't understand why they have to do this.

http://www.autosport.com/news/report.php/id/100969

[strad]

At first I thought you said scraped...Scrapped?? JT Why in the world would they have to scrap them?

[simieski]

Someone at work asked me the same question today. The best I could come up with was that if the tyres were to be saved to be used at the next grand pix weekend their performance might alter over time, so if some of these were given to teams while others teams received fresh rubber it could bring an issue of fairness into it all. Possibly also to do with same/consecutive batch numbers to be used each race again for fairness.

Seems an unnecessary waste though, makes a bit of a mockery of the cost cutting.

[Jersey Tom]

Once the tires are mounted on wheels Pirelli may have a policy of scrapping dismounts to avoid any potential for torn beads or any other damage from the process.

Inventory of tires which haven't been mounted I'm sure are reused down the road.

[marcush.]

you are saying they use tyres from diferent batch production for the same event?
I´d cry out loud if I were a victim of this...even though who knows how they verify that first and last of the productiuon run is THE same and variance from batch to batch is also at the border of detectable...and how do you quantify this...
i could imagine a lot of environmental influences will alter the behaviour and response of a race tyre- consistency over long periods of storage under uncontrolled conditions is surely not a priority in race tyre development ...
I was told years ago (from race tyre supply )that pirellis batch to batch variance is considerable in compound and carcass even measurable very easily with static springrate measurements and shore hardness sampling.

[nacho]

Maybe 200 tires rather than 200 sets?

There's been discussion in MotoGP about tire performance and production date, the older the tire gets the less it performs.

[Jersey Tom]

you are saying they use tyres from diferent batch production for the same event?
I´d cry out loud if I were a victim of this...even though who knows how they verify that first and last of the productiuon run is THE same and variance from batch to batch is also at the border of detectable...and how do you quantify this...
i could imagine a lot of environmental influences will alter the behaviour and response of a race tyre- consistency over long periods of storage under uncontrolled conditions is surely not a priority in race tyre development ...
I was told years ago (from race tyre supply )that pirellis batch to batch variance is considerable in compound and carcass even measurable very easily with static springrate measurements and shore hardness sampling.

I don't think I'd care if I "fell victim" to this, to be honest. Don't think it matters one way or the other. If you have a good tire supplier with good manufacturing, batch to batch variation within several months or a season shouldn't be a big deal. If the manufacturer is crap, then the tires WITHIN a batch probably have some variation and you're hosed anyway.

Even then, some aspects of "variation" might be important, others are trivial. Not an efficient use of time to try and chase down all of them. Or worst case, burn through your older tires in practice and save your newer ones for Q and race.

Then there are some suppliers / series where you are intentionally not given build date information, because everyone would make such a damn fuss over finding tires a month newer than some other one or some malarkey like that. Good way to prevent people about worrying about things they shouldn't, and let them focus on bigger things.

[machin]

Anyone have a link which describes what happens to used tyres after a grand prix weekend? Recycled? Land fill?

[strad]

I think I understand JT...the beads have been stretched and even minorly torn so for overall safety they scrap them. Thank You

[spinmastermic]

Anyone have a link which describes what happens to used tyres after a grand prix weekend? Recycled? Land fill?

This should explain everything

http://www.formula1.com/news/features/2012/5/13368.html

[Jersey Tom]

I think I understand JT...the beads have been stretched and even minorly torn so for overall safety they scrap them. Thank You

That would be my presumption, yes. I could be wrong. Tearing up beads can happen even when dismounting passenger car tires. Really it's not the bead itself as that's generally a cable of steel, but the rubber around that area which seals it to the wheel. Then again if Pirelli were using carbon beads or something in F1 I suppose you'd have even more potential for damage.

To circle back on the age thing and batch variation as well... here's another perspective to put it in: It can be challenging in itself just extracting the most potential from a spec of tires on a given weekend even if they were all 100% identical. It could be easy to leave performance on the table. So my line of reasoning is sort that out first and THEN worry about set to set variation. Of course one could make the counter argument that you might not be getting a true read on your car if every tire set varies enough. Depends on the order of things and which variables you feel are most influential to the car.

Personally I think tire age variation would be lower on the list than some other things.

[marcush.]

I think I understand JT...the beads have been stretched and even minorly torn so for overall safety they scrap them. Thank You

That would be my presumption, yes. I could be wrong. Tearing up beads can happen even when dismounting passenger car tires. Really it's not the bead itself as that's generally a cable of steel, but the rubber around that area which seals it to the wheel. Then again if Pirelli were using carbon beads or something in F1 I suppose you'd have even more potential for damage.

To circle back on the age thing and batch variation as well... here's another perspective to put it in: It can be challenging in itself just extracting the most potential from a spec of tires on a given weekend even if they were all 100% identical. It could be easy to leave performance on the table. So my line of reasoning is sort that out first and THEN worry about set to set variation. Of course one could make the counter argument that you might not be getting a true read on your car if every tire set varies enough. Depends on the order of things and which variables you feel are most influential to the car.

Personally I think tire age variation would be lower on the list than some other things.

I see from where you are coming from ..but your reasoning implies the tyre variation causes by process parameters up the road till you get hold of your tyre allocation is a minor influence compared to what you as a team or the driver do with the tyre supplied.
IF the influence of the tyre History before delivery to you has a significant impact then you might get wrong feedback from
your evaluations how to use the tyres ,as the variance in tyre supplied has somewhat masked the results of your own optimisation.

On the other hand with tyres different front and rear in size and everything ,I don´t understand how you could possibly get a bad set of tyres due to production issues....you may get one bad performer -or a inconsistant set with a rather big spread of tyre characteristics side to side / front rear balance....but I´d guess the teams do match their tyre allocation to optimise with the tools they have?

what about Dufournier tools ? has anyone worked with these?

http://www.dufournier-technologies.com/ ... uits_2.htm

[machin]

This should explain everything

http://www.formula1.com/news/features/2012/5/13368.html

good stuff, thanks, here's the bit I was after:

All remaining tyres, both used and unused, are taken off their
rims and then transported back to Didcot. When they arrive, the
tyres are taken to a specialised plant where they are shredded and
then burned at very high temperature in order to produce fuel for
cement factories. The material produced in this process can also
be used for road surfaces and other industrial applications.

[Jersey Tom]

what about Dufournier tools ? has anyone worked with these?

http://www.dufournier-technologies.com/ ... uits_2.htm

Familiar with them. It would certainly be convenient, particularly for smaller teams or organizations, to outsource their tire model fitting etc.

Some of their other resources I think are overkill. Trying to do thermo-mechanical tire models... going to require a lot of characterization. Not always practical if your tire construction or tread compounds change frequently. Besides, even if you add that level of model complexity that's the "easy" part... exploiting and making use of it is an immense challenge.

[marcush.]

dismounting of tyres is possibly not a big consideration in the Quality process of a tyre manufacturer -it is somwhat uncontrolled .And you may or may not stress the tyre overly pushing the bead over the hump -which was not designed by
pirelli - I´d think it´s just one risk less .