F1technical.net

Lycoming wrote:I believe pirelli can make a far more durable tyre than what they currently have, without large detriment to the other parameters. Hembery said that it would have been easier for them to produce a tyre that lasts the entire race distance. That said, I don't believe that they could make a tyre that was as good as the bridgestones in '10. At least, not yet. You cannot compete with the years of experience that Bridgestone had by then. I don't feel prepared to comment on how their resources compare though. Bridgestone may be a bigger company, but how much effort did each put into their F1 program? in any case, my argument about them having more experience still stands.

It would infact take a long while before Pirelli will be able to get to the standard of Bridgestone. Don't forget: Bridgestone not only had years of experience, they had quite some years a tyre war with Michelin, in which tyre performance, even grooved ones, increased by alot. Pirelli has no real incentives, beyond complaints of the teams, to increase tyre performance. Just to sum up: when Pirelli started back in 2011 during their tests, Bridgestone send up an advisory team to help them. During a wet day they tested the extreme wets. Pirelli was quite satisfied with the performance, with the tyres having lasted 12-15 laps or so. The bridgestone team on the other hand were astounded they only lasted that long, remarking that their tyres could, if the track was kept sufficiently wet, last an entire race.
Can Pirelli make more durable tyres? They can, infact that's why they developed so quickly a hard tyre for next year, which is softer then the current one yet lasts longer. But I don't really see the point of that. Tyre wear isn't the issue for teams. Getting the tyres in the right operating window is, and I think that is ALOT more difficult for pirelli to correct.

marcush. wrote:What i have not heard of is Pirelli supplying anything like rig testing data or conclusions they derived from it.The teams have no access to the tyres for rig testing .if I´m correct this is explicitely outlawed .

If that's the case I'd be pretty frustrated knowing university students doing Formula SAE are getting more extensive F&M data than F1.

Jersey Tom wrote: Heat as in running temperature. In general, and certainly for the purposes of an internet forum, it's a pretty good visualization of the trade offs that a company like Pirelli has to consider when developing tires (be they race or consumer).

Heat generally being bad, if they want to bring a higher grip tread rubber it's going to come at the expense of running hotter (more hysteretic) and/or wearing faster (softer/weaker). If you want better longevity you're either going to have to sacrifice some grip or put more rubber on the thing (hotter). If heat is a concern you either have to take rubber out of the thing or take some grip out.

Or if you want to get better in an area without sacrificing elsewhere, you need R&D.

I'm beginning to suspect that you (implicitly) mean heat capacity. A higher heat capacity results in a higher mean running temperature. The problem is that more heat (thermal energy) is needed to warm up the tire to that temperature and to keep it at that temperature.
But the optimal running temperature is dependent on your application and the rubber mixture. Simply increasing the heat capacity will give more grip (higher temperature increases elasticity) but lowers tire life (higher temperature decreases tensile strength, that could be offset somewhat by smoothing the heat spikes).
So changes in heat capacity always mean changes in compound (to increase tensile strength).

It's not just about tensile strength; heat causes the rubber to cure and harden, which screws the tire.

Nothing to do with heat capacity. Loss modulus, yes (or any variety of measure of it, normalized to stiffness etc) - heat capacity no.

My point is that if you bring a higher grip tread by virtue of being more hysteretic... it's going to be hard to avoid it running hotter, and typically the things you do to get there are going to sacrifice strength and wear longevity. Becomes pretty clear when you're running tires at a race track.. there's a limit to how "soft/grippy" of a tread you can go before either (a) you're blistering and/or (b) you're wearing them out way too fast.

That whole discussion is relating to what options a tire manufacturer has in bringing different options to a race track.. not talking about what a team can try to do (if anything) to balance things against each other with one tire spec.

Jersey Tom wrote:Nothing to do with heat capacity. Loss modulus, yes (or any variety of measure of it, normalized to stiffness etc) - heat capacity no.

My point is that if you bring a higher grip tread by virtue of being more hysteretic... it's going to be hard to avoid it running hotter, and typically the things you do to get there are going to sacrifice strength and wear longevity. Becomes pretty clear when you're running tires at a race track.. there's a limit to how "soft/grippy" of a tread you can go before either (a) you're blistering and/or (b) you're wearing them out way too fast.

So it's about the deformation of the contact patch by the tire rolling?

Jersey Tom wrote: That whole discussion is relating to what options a tire manufacturer has in bringing different options to a race track.. not talking about what a team can try to do (if anything) to balance things against each other with one tire spec.

I'm aware of that, although tire pressure plays an important role and in F1 they are allowed to change it.

superdread wrote:

Jersey Tom wrote:Nothing to do with heat capacity. Loss modulus, yes (or any variety of measure of it, normalized to stiffness etc) - heat capacity no.

My point is that if you bring a higher grip tread by virtue of being more hysteretic... it's going to be hard to avoid it running hotter, and typically the things you do to get there are going to sacrifice strength and wear longevity. Becomes pretty clear when you're running tires at a race track.. there's a limit to how "soft/grippy" of a tread you can go before either (a) you're blistering and/or (b) you're wearing them out way too fast.

So its about the deformation of the contact patch by the tire rolling?

How much energy is lost per cycle of the tire, yes.

As it was rightfully noticed Pirelli don't really need to improve all aspects of their tyres. Even if they would "accidentally" find a way to do so, they might not pursue it.

If I was Mr. Hembery and an engineer came to me and said they could make the tyres better, but it would cost $1M more to manufacture, I would tell him to better find a way how to keep tyres the same, and spend $1M less. It's all about priorities, and I feel Pirelli's F1 program is not about R&D. And I can't really blame them

Jersey Tom wrote:

superdread wrote: So its about the deformation of the contact patch by the tire rolling?

How much energy is lost per cycle of the tire, yes.

The gain in grip would be purely because of the increase in contact patch, wouldn't it?

What increase? A big part of tire "grip" is generation of force through hysteretic loss. As a very broad statement, more hysteresis leads to both more "grip" but also heat as well.

Just a thought - given quite a few people seem to dislike tyre management so much - and prefer to just see people going balls-out every lap, is it possible to make a tyre that doesn't "respond" well to being managed? ie being managed really doesn't do it much good, and it just wears and/or degrades equally to a tyre that isn't being "managed?"

I'd think that's the only way that the drivers would push, really. If you just made the tyres more durable I suspect they would then try to extend what they have now, and just return to how things were in 2010 (if all of that makes sense)

DISCLAIMER - I am NOT saying this is what they should do - I am merely throwing out this question out

Ray, are you saying to do the opposite of what we're seeing this year? That is, the harder you drive the tyre the better it gets? If so, thats a good idea. You'd think they could do that.

The drivers are already conserving fuel, so double conserving is just a slap in the face of racing. Having tyres that respond and react positively to being pushed would certainly change the strategy and I think it would be for the better. You might actually see drivers just gun the thing from lap one for once.

I don't think you can ever make a tyre that improves as you push (and therefore abuse it) more. Your slip angles increase, heat going into the tyres increase, etc.

But what I mean is making a tyre that almost has "a set expiry lap" - eg a tyre that, driven 5 seconds off the pace (tyre management) lasts the same, or at least a very similar, distance, to the tyre driven at full bore.

Ie the amount of slowing down you'd have to do to eke an extra lap into a stint really is so ridiculous that it makes pushing the better strategy so basically where the drivers say, "hey - they're going to last 15 laps on the pace, but only 16 laps off the pace, so we might as well push"

Ie as I said - a tyre that doesn't respond as well to management - as opposed to just making harder/more durable compounds, because the increased durability could just mean the drivers stop less (but still with tyre management)

I still don't think, nor will I ever, that a race tyre needs to play a part in the race outcome. It should be considered the same as a safety item - built to specs for the greatest result possible and the same for all with open and in-depth data available.

Having a component that is designed to fail - defeats every reason why teams go racing.

So on that basis we'd have no pit stops and everlasting tyres with full grip to the end? So no more strategy?