Just to compress this into one slightly unmanageable long post..
Ah yes, post length and quoting management becomes an issue, but that doesn't matter when it has substance
I'm aware of Pacejka's Magic Formula. If it is calculated for 4 wheels of, say 16 cars, and computed at a high rate, that is indeed a refinement over the simpler methods. But of course it's a
magic formula, not true physics (I don't really like that term), which gives the behavior with acceptable limits for our sim. And that is, as I mentioned, good engineering.
I also know about the brush model, which is good since it deals with deformation in all dimension. It needs to be computed with a fair resolution, of course (many brushes). If S2U use a brush model, that is probably good enough. But it's still not modeling chemical compounds.
There is no evidence there for his conclusion. He does not present any measurements for the effects of (the lack of) tire widths. The total relative lateral grip depends on a lot more factors than just the tire compound and width; e.g. weight, center of gravity, suspension geometry and setup. What he has to go on is the increased grip with increasing grippy tires, and that's where I'd expect to see the same relative increase, given that the other factors mentioned above are constant. In any case, it's faulty "science".
It's not perfectly linear with wider tyres and depends on other things now?
Yes, but here I'm bringing in other variables that differs between two cars and contribute to the overall mechanical grip of the whole car, not just an isolated tire contact patch. I thought the distinction between those was self evident in that paragraph, taking the context into consideration (Cooper vs ZR1). I should have been more clear.
Again I can't help but think you're leaving out the most grievous wound inflicted here - the total lack of any impact on the longitudinal behaviour of the tyre.
I did mention "any angle", but the again I wasn't talking about whether any particular sim models this or that well. Additionally, I'm not the one that was attempting to analyze how GT5 does things.
If I can presume a bit here - it seems like you think there are really only two methods anyone can use.
1) full fluid dynamics simulation at an atomic scale
2) lookup tables
There are many many many steps between those two things
Your presumption is wrong; I'm well aware of that. I mentioned the two as being the (almost) full-on and the simple variants. As hinted on previously, I'm not of the black and white -only persuasion
I'll give you that there's modeling going on, but in a simplified form, using tables and coefficients that covers for a larger and more complex underlying dynamic system, ref. True Physics as discussed earlier in the thread. E.g. tire wall flex is most probably a coefficient and/or a table, not a real time simulation of actual tire deformation (which is very complex and needs at least a
FEM process).
Giving tires with different compounds, widths, profiles and construction different behaviour can all be done using different sets of tables and coefficients.
Not true. Even without any pure "physics" data changing, tyre behaviour can be altered in Shift simply by changing to a different tyre model (that is, the 3d object model itself) on the car. Two things exist in those - geometry defining the tyre's visual appearance, and bones attached to the left/right sidewall, rim, and tread surface.
I think I was saying precisely what you say, i.e. that you only need to swap out some data, e.g. tables and coefficients, to model a different tire (graphic representation aside).
Edit: I don't have the PC version of S2U, so thank you for the details that can be gleamed from it!
I musty again emphasize that my argument didn't concern any particular sim. It was a general talk about two things. Firstly that the methods used in the referenced article/posting doesn't provide evidence of how, or at what level, the physics is implemented. And secondly, I tried to shed some light on the fact that the physics used in sims is a simplified version, and that this is often "good enough".
I think you may have misread me on a few points there(?) I'm not a native English speaker, so some things may come out in a clumsy way. BTW, where are you from? Anyway, your posting is very interesting as it expands on the issue of where we are between the simpler representations and actual physics 👍
Edit 2: I'd be interested in a response, merely to check that we're not talking past each other - if I'm not mistaken we have pretty much the same understanding of the points being discussed.
DJ
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) things to reduce certain other aspects of grip based on the whole car yaw angle and rotational speed of the tyres 
) then see how long it takes for the tires to heat up... its been already proven that heating up the tires does have impact on them and their performance...
).
