2015 tyre blanket ban connected to low profile tyre

[WhiteBlue]

http://www.f1today.net/en/news/pirelli- ... n-for-2015

There seems to be a conundrum. In order to save cost by banning tyre warmers the teams may have to re design the whole suspension for low profile tyres which will probably cost a lot more. I'm curious how this one will play out.

[gray41]

I really hope we don't go down the low profile route.

[Tommy Cookers]

if it leads to F1 tyres doing the tyre's job and F1 suspensions doing the suspension's job that's good ?
current F1 tyres are a long way from low profile

[WhiteBlue]

I do agree with Tommy there.

[MOWOG]

Tires are such an important part of the package. Michelin has been advocating for larger wheels instead of the 14" wheels the sport presently uses. Presumably with a little fender modifications, a current F1 wheel and tire would fit nicely on a 1980 Accord, which is primarily why Michelin wants the sport to go larger. After all, they DO want to sell a few tires into the bargain if they ever get involved in the sport again.

No matter how many engineers are on the pit wall or back home at the factory, everything about how the car performs on track ultimately comes down to a relatively small contact patch. Tires have a significant effect on aerodynamics as well, which is why we saw F1 cars with 4 small front wheels instead of two large ones some time ago.

Low profile tires also provide less sidewall flex, so suspension adjustments would inevitably be required.

All in all, as is normal in Formula One, saving money will cost a lot more than what is saved!

Perhaps one day we will see Formula One race on something like these?

[Holm86]

if it leads to F1 tyres doing the tyre's job and F1 suspensions doing the suspension's job that's good ?
current F1 tyres are a long way from low profile

I agree. But if the solution is to go to bigger rims and smaller profile on the tires then the tire warmer ban should be postponed to 2016. Together with an introduction of the new wheels. That would give teams enough time to starte redesigning the suspension.

[Jersey Tom]

Michelin has been advocating for larger wheels instead of the 14" wheels the sport presently uses. Presumably with a little fender modifications, a current F1 wheel and tire would fit nicely on a 1980 Accord, which is primarily why Michelin wants the sport to go larger.

My speculation would be Michelin would have wanted larger wheels just so they don't need to invest in all the 13" build equipment for tires of that size (and wide ply servers, etc etc). I'd guess it has nothing to do with anything concerning consumer tires.

As for low profile tires - I don't see it happening. From that article I see that as more a side comment than anything. Some interesting bits...

If we had a lower profile tyre with a stiffer sidewall and a lower volume of air cavity, it would certainly be much easier to manage.

I'd debate that. pV = nRT. If a tire goes from Temperature A to Temperature B the ratio of internal inflation pressure should be the same (secondary effects aside) regardless of air volume.

Pirelli boss Paul Hembery said the main issue is tyre pressure, as the difference between a cold and a hot tyre is significant.

How much does a F1 tire build up pressure between hot and cold? ~5 psi maybe? (Guessing here). There are other open wheel series who can manage that. There are closed wheel race series where the pressure builds up ~25 psi from cold to hot, and they can manage it.

Now with all that said, it's really a question of who is incurring costs and where. Change is expensive. Tire blanket ban I'd imagine will be quite expensive for Pirelli in compound development, probably likewise expensive for teams in getting better understanding of broader temperature ranges or figuring out how fundamentally different tread compounds behave, how to get additional temperature, whatever.

Going to larger wheel size and lower profile tires would be massively expensive for Pirelli.. cutting all new molds, big development programs, more track tests, and the like. Similarly very high cost for teams.. maybe not from a redesign side since they'd potentially be making all new parts every year anyway.. but certainly from a development and test perspective.

Really way too late in 2014 already to be making a change to a different wheel size.

Don't get me wrong, I'm all for shaking up rules every so often - changes the running order. But it doesn't need to be huge changes every year. If we were to end up in 2016 with quiet turbo'd cars castrated by fuel flow, and weird looking (for an open wheel car) low profile tires, and a bunch of contrived gizmos between DRS and ERS and brake by wire, etc etc.. what exactly have we fundamentally gained?

[Holm86]

If we had a lower profile tyre with a stiffer sidewall and a lower volume of air cavity, it would certainly be much easier to manage.

I'd debate that. pV = nRT. If a tire goes from Temperature A to Temperature B the ratio of internal inflation pressure should be the same (secondary effects aside) regardless of air volume.

This is true. But you need to consider that the more air the longer it takes to heat up the air. So even if the pressure differences are the same the time between when those temperatures is achived changes. And that could be quite a lot.

[lebesset]

initially pirelli said they wouldn't enter F1 unless low profile was adopted , not surprising as they introduced the concept more than 40 years ago with 50 series P7 [ I happened to notice that they have introduced updated versions for historic rally car competition ]
but , as usual , the F1 teams resisted change ...and the rest is history ...or should I say historic

[WhiteBlue]

If we had a lower profile tyre with a stiffer sidewall and a lower volume of air cavity, it would certainly be much easier to manage.

I'd debate that. pV = nRT. If a tire goes from Temperature A to Temperature B the ratio of internal inflation pressure should be the same (secondary effects aside) regardless of air volume.

I disagree and think it will be easier as Symmonds says. At the moment you get two spring rates. One from the side wall and one from the air or tyre gas cushion. In the low profile tyre the side wall will be so stiff you can almost neglect it. It makes life much easier for the guys who have to stay on top of things to use simpler models.

[Tim.Wright]

I'm not sure its correct to say that the air acts as a significant spring in the tyre stiffness equation. I think the sidewall stiffness is mainly a product of the sidewall construction. The air acts merely as a preloading mechanism.

The spring rate coming from the air would be only due to the percentage change in air volume due to deformation which I think would actually be larger if the volume is smaller to start with.

[WhiteBlue]

Whatever happens the tyre spring rate will probably be negligeable compared with the suspension spring rate. Perhaps that is what Symmonds had in mind.

[Jersey Tom]

One [spring rate] from the side wall and one from the air or tyre gas cushion.

There is absolutely zero direct effect from the air pressure on tire spring rate. Physically impossible.

[Tim.Wright]

Not even from the same mechanism like a gas accumulator? Where the tyre deformation changes the gas volume and therefore the pressure?

[Jersey Tom]

Not even from the same mechanism like a gas accumulator? Where the tyre deformation changes the gas volume and therefore the pressure?

Even if pressure goes up, it will still act uniformly across the surface of the wheel. All forces cancel each other out.