TO DEVS: Are tires working properly?

Discussion in 'General Discussion' started by williang83, Dec 1, 2019.

  1. williang83

    williang83 Registered

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    The tire black box system output doesn't seem right to me. Are they dynamic? Very! Are tire working as IRL or at least resembling it? It really doesn't seem so.
    • Compound, wear and grip aside they all feel the same. There is little to none difference when it comes to working window (both temperature and pressure). It's all a matter of which will wear sooner.
    • Pressure, playing with pressure does not affect the temperature in a sensible way and as expected, at least today.
    • Temperature, not only they are unaffected by track temperature, which in a known fact, but also the missing clear working range and obvious pressure correlation makes the whole tires logic....well illogical. Actually right now they overheat very easily, no matter the compound or track temperature. The only thing that really affect the temperature is the camber but of course the degree of freedom is quite low since you still need to manage a proper temperature spread.
    • Grip, there's little to debate here. It is known that sims have way lesser grip than IRL and RF2 is not immune to this.
    In other words, the black box output really is not what i would expect regardless we are talking about a very complex multi contact points system. Honestly speaking, in an overall point of view, somehow i've seen more credible behavior in very old game (eg. GP series) which i'm almost sure that it was using a simpler system.

    What i find curious is the fact that rF2 tires are so praised in the forum, yet they feel off. Again if your meter is dynamic factor then they are great, but if your meter is RL alike behavior then they at least seems off. I get that not only it has multi contact points but also they flex which means the contacts points are not static but they deform, which is great. However dynamic aside, are the final output undoubtedly more realistic than ever? Very debatable and my answer would be NO!

    Don't get me wrong, I love dynamic tires but i would trade that every day for a less dynamic but more RL alike behavior.
     
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  2. Lazza

    Lazza Registered

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    [citation needed]
     
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  3. mantasisg

    mantasisg Registered

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    Well grip is the whole thing, so there is indeed lots of to debate about that. Also there is not just grip, grip consists of many grip variables, for example static friction and kinetic friction, then it goes various sensitivities to various variables, there is so much to it - the books are written, also most of the setup stuff is there to manipulate tire grip.

    I disagree that simulations has lesser grip than IRL, I think net grip might usually be even higher than real life, as far as my observations goes, and what can be gathered as fastest laptimes real vs simulation. What could very likely be wrong is how the figures are implemented. For example, tire could have too little static friction, and too much sliding friction, which make it seem like it has much less grip than a tire that has high static friction, but low kinetic (sliding) friction, while both would have same (or very similar) amount of actual grip. If someone disagree with that I am open to discuss why. Then there are sliding speeds that affect sliding friction, load sensitivity effects, thermal effects, and lots of other stuff.

    Last but not least there is a possible distortion of the senses and expectations. Like going into 40km/h turn at 60km/h and wondering why on earth the car is sliding :D
     
  4. williang83

    williang83 Registered

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    Of course when talking about a system simulation the system can consist of many subsystem which itself can consist of even more subsystem. It all depends on how deep you want your simulation to be, however going deeper means increasing complexity and most of time not only it is not needed but also it might be counterproductive and actually providing worse realism. As matter of fact it is all about the inputs and the output/outputs, as long as the output is realistic you are go to go.

    You are talking about subsystem simulation, in this case detailed grip. I'm talking about the overall black box which sorry is completely lacking in rF2 contrary to what people use to say.
     
  5. mantasisg

    mantasisg Registered

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    I don't think that you are right. As much as I understand realism is... realism, there are certain know effects that are described through parameters that are calculated through various formulas and managed by the code. I don't know what you have in mind when you talk about systems, subsystems and boxes. I just replied about how grip works, I don't know why you replied to me talking about apparently software architecture/code side of stuff I have no idea about that.

    And I totally disagree with your way of thinking about complexity, obviously more functions and more features will exponentially increase the complexity, there is no way around it, I suppose it only can get smoothed so much depending on how much of a genius the coders are. Your idea would make more sense if you'd have some specific example of complexity to share, and a good argument why it is unnecessarily complex.

    Speaking about "only inputs/outputs", I don't think you understand what a tiny bit of an iceberg those actually are.
     
  6. Emery

    Emery Registered

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    Demonstrably false. Put the car on a skidpad of known diameter and time your laps. Or use telemetry. The grip is there. You may not be perceiving the grip through your chosen steering controller, but that is a set-up issue, not a game issue.
     
  7. avenger82

    avenger82 Registered

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    Are you sure? Old ISI tires, even early CPM versions are quite different (i.e. they overheat much more when sliding).

    That's my impression too, but I haven't verified it "scientifically". But for instance in rF2 you're virtually always fastest with lowest possible pressure. I think in some conditions lowest pressure would cause overheating, thus significant performance drop.

    In my case
    I rarely have this problem, especially with newer tires. But compound and pressure has big impact in Assetto Corsa. Sometimes with soft compound I find it impossible to drive fast.
    I've read track temperature doesn't affect tires in rF2, but ambient temps also not affect at all?

    Nice one! Seriously if you have access, check iRacing forums:)
     
  8. Ronnie

    Ronnie Registered

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    1. That's true that early CPM that came with Stock cars and first version of ISI karts (those were first ever "car" to get CPM tire - piece of trivia for people who are not that long with rf2) and they were a revolution compared to old tires which were extremely prone to overheating and rear sliding. Old CPM fixed the rear sliding but they had lots of flaws still.
    2. Pressure DOES influence temperatures for stuff like carcass however differences between extra low and slightly higher pressures is usually from few deg C to max 10 C with same driving. It does make a difference but usually it gets offset by higher pressure being slower. So I would say that pressure doesn't have big enough influence over rubber, carcass temperature buildup. Talking about pressure vs grip, there is a problem of that there is NO penalty (safety wise) for running low pressures. All racing teams do all they can to lower pressures due to higher grip. The problem is that it isn't safe because you are risking tire failure. So what gives you grip is mostly temp, having lower pressures means quicker heat buildup. So when people say they need to build up pressure before they push is not that they need pressure to get peak grip, it's the temperature rising increasing the pressure and the subproduct of pressure buildup is more progressive and consistent behavior of a tire so it's easier to drive at the current limit, but actual grip peak was before tires reached pressure equilibrium and after they reached working range temperature because that's when chemical reactions are taking place inside the tire's compound making it actually "working", flexing, springing at the level giving highest grip.

    There was this old video from early 2000s from Schumacher's T-Cam during Spa GP. He went through les combes behind SC so his tire temps dropped and therefore pressure dropped so low (he started with extremely low pressures, far below safety recommendations) that his loaded tire started acting like a shaked jelly. Like it was about to explode (which it could if it did it a few more times). He was known for using extremely low pressures to get maximum grip while risking failure if those get too low. That's why not many teams used to do that, and that's why nowadays Pirelli mandates minimal pressures which are far beyond what they could have been using if they wanted to take more risk. rF2 doesn't simulate tire failure from too low pressure so everyone uses it. Simple as that.

    3. Overheating? Depends what people think overheating is. I've known people that thought that everything above 90-95C rubber temp is overheating which is not true at all. Modern tire's working range gets much higher than that.

    About tire temperature, ambient temp no affecting the track. That's not true. Track/ambient temp AFFECTS tires... It's just one temp working. Your crew chief could tell you that temp is rising or falling etc, UI could show you 16 C but it doesn't matter because tires are fed with one fixed temp. So what we need is for it to change to dynamic so tires could actually get variable data and not a static one. Also lack of wind has it's toll on how tires heat or rather cool down.

    EDIT:
    @LokiD That's the video. I watched it live so many years ago and remembered it, kept it at the back of my head. Few years ago I stumbled upon exactly this or similar video showing exactly the same situation. I knew there was this video somewhere on the internet but didn't get myself to look for it. Thanks for the effort.
     
    Last edited: Dec 2, 2019
  9. LokiD

    LokiD Registered

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    Guys wanted to see this for myself Wow he's right.

     
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  10. LokiD

    LokiD Registered

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    I probably watched it live and I think I remember seeing it at the time. But to recall it wow some memory.
     

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