Tyre pressures

Discussion in 'General Discussion' started by Jeremy Talbot, Jul 10, 2018.

  1. Devin

    Devin Member Staff Member

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    ^it's funny because just 3 posts earlier I've explained exactly what is happening and why that is the case, and just a few posts before that I went into detail about the low pressure limits. And no, unlike you I don't speak from "having seen interviews with people who know race engineers", I speak from actual personal experience and evidence ;)

    Oh by the way, if optimal pressures in rF2 aren't a thing, please explain to me why I'm faster on longruns when I don't use the lowest pressures, but instead get those just right.


    Also I've just realised something even funnier than that: Whenever any AC or pCARS fanboys try to criticise rF2 and actually get proper explainations and proof why their claims are incorrect, they just go the "you're just a fanboy" rail and try to use that as an argument to disprove facts. Do yourselves a favour and just leave this stuff out of here. Last time someone did that, and eventually went onto the rF2 discord with it, he got banned.
     
  2. patchedupdemon

    patchedupdemon Registered

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    If you’re talking over a lap,yes lowest allowed in rf2 is fastest,over a race run or stint,no they are not fastest and you soon get the effects you describe.

    Also re tyre features,you can have all the features in the world,but if they are simulated in a very basic way,then the tyre model that has less but more in depth modelled features is still superior
     
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  3. Kevin Ryan

    Kevin Ryan Registered

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    I don't agree it's faster over a stint either. It might feel better with higher pressures but as Florian said the lap times are slower and the car is sluggish.
     
  4. patchedupdemon

    patchedupdemon Registered

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    Not in my experience,with the Lowest temps I suffer from a loose back end after say 8laps,raising the temps to get them even and as best spread across the tyres as possible,is the way I produce the best race time over the distance,I like higher even still because it takes away the sluggish and slow response of the low pressure setup

    No offence but maybe it’s your driving style that is producing the effects you get,one should always look to that first before changing anything else

    Some folks think overdriving is driving on limit,these are infact two very different things
     
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  5. Andregee

    Andregee Registered

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    I can confirm that. I am allways faster with the lowest pressure with Gt3 , even over 2 hours on one tyre set. I also can't notice more overheating with lowest pressure in Motec. I all can say is that the los of grip over 180-190 kpa pressure caused by higher starting pressure is very easy to feel. The Gte tend to oversteer with lowest pressure all around, the cars have to much grip at the front with lowest pressure
    . That's the reason why the rear is overheating. Using a Bit more pressure at the front reduces the grip there, the car understeers more and the rear tyres stay cooler. You can also adjust the anti rollbar or spring stiffnes to compensate that. That has nothing to do with to low tyre pressure meaning more heat up, its only a question of the balance
     
    Last edited: Jul 14, 2018
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  6. Stefan_L_01

    Stefan_L_01 Registered

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    You can balance a car better if you look for same pressure front / rear once they are hot. If your set feels fine for 2 laps and gets loose after, probably the rear pressure increases more. Which is in turn a proof that pressure increase lowers grip which is also my opinion.After all the tire works like a spring and usually softer is better un rF2 since long time, rF1 actually. I think also dampers are usually set to rather low level.
    Claiming this or that is better is a nonsense as there might be drivers out there being faster the other way. Only the best could tell probably. Ask the Top10 of a competition race
     
  7. Andregee

    Andregee Registered

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    Yes the rear tyre pressure increases more with the GTE and thats the reason while the standard setup comes with 10kpa more at the front. After a few laps all tyres have the same pressure and the balance is good. Starting with lowest pressure at the Front and rear let the rear tyre pressure end in a higher value and you will loose more grip there than at the front. To make it clear, driving with lowest pressure at the rear and High pressure at the front let the front tyres getting very hot caused by heavy understeer while the rear tyres stay cool.
     
    Last edited: Jul 14, 2018
  8. Florian W.

    Florian W. Registered

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    Obviously my argument was based on feelings, did not know that the track temp has no influence on the tires too.
    This was the orginal post https://www.gtplanet.net/forum/threads/car-behavior-and-tire-temps-after-patch-2-0.361962/
    Pirelli/michelin and Hankook were stating that the ideal pressure is 30psi -32 psi. Again we do not reach that in rf2 (not even overdriving the car)
    I changed the pressure to reach that 30psi minimum but it feels worse (thought it solves the heating issue too) , 1:15.1 with the new BMW on road atlanta (fastest of 44 drivers), so i think i kinda know "how to drive". In the race i get slower and slower after 2-3 laps (temps go up), i start coasting around. Its impossible to hold 1:16.0 laptimes for me, normally i expect to get faster with less fuel ... (still kinda new to the game) I never felt i was pushing the car, just managing the tires, maybe thats how it is in real life ... I also tried to run medium, but got the same result (slower fastest lap but same fall off)

    Orginal post from lead dev pcar2: http://forum.projectcarsgame.com/showthread.php?57541-Project-CARS-2-Tyre-Temps

    Just wondering why we are so far away from the ideal pressure. (If that is not the real pressure, but we have to look at "gas pressure" how do we access this information?)
     
    Last edited: Jul 14, 2018
  9. Andregee

    Andregee Registered

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    I can say that the pressure Build up in Cars 2 has nearly the same level like in Rfactor 2 on a 29 degree Celsius track and the starting pressure of the Porsche Rsr is nearly the same like in Rfactor 2. But the track temperatures are often higher an effects the tyre temps and like I said you can work with the brake duct too so that its easier to reach higher pressure values
     
  10. bwana

    bwana Registered

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    Certainly it seems default pressures are too high and l agree with others that a lowest pressure is best for a short QUAL run .. you can find optimism pressures AFTER you have set your suspension variables , l always drop all pressures around 4 psi and then work on camber , toe springs /dampers and roll bars and THEN go back to tire pressure tweaks .. it works
     
  11. Kevin Ryan

    Kevin Ryan Registered

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    @Devin Could you give me some example tire pressures to test so I can compare? Maybe I've been missing out, it's just all my experience in rf2 is telling me otherwise.
    You misquoted me very badly btw. That's not nice. I said my sources were race engineers, not people who know race engineers.
    And I only play rf2 so don't be making assumptions about me.
     
  12. Lazza

    Lazza Registered

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    The danger with logic is it's quite often wrong. In this case there is a distinct possibility that the tendency for the tyre to return to its normal, unloaded, shape will vary with its current load and shape. So a reduction of grip won't necessarily result in less deformation as the tyre is already in a deformed state and may be 'pushing back' with less force. But we can theorize all day without really knowing. ('pissing in the wind' comes to mind)

    @Devin One point I'd pick you up on is air naturally being worse because of expansion. All gases expand, the problem with compressed air is varying levels of moisture which then change the amount of expansion. Fully agree with the opinion that the main thing missing in rF2 in terms of this discussion is failure modes related to pressures being too low, so the real life deterrent to running lower pressures doesn't exist here.

    And things like that, brake temperature not transferring to the wheels and tyres, static track temperature, are features we would all like to see in rF2 because we think the core tyre model is superior. Unfortunately the end user only feels that core model (mostly), while some of the more obvious numbers and effects (like tyres delaminating due to excessive camber or low pressure) don't work as expected.
     
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  13. Daniel Surace

    Daniel Surace Registered

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    correct me if I'm wrong, i have heard it somewhere perhaps Michael Borda mentioned, but don't hold me to any of this. that there is issues with low pressures and Rfactor 2 Tyre model. I'm sure you cannot even run the pressure in rfactor2 low enough in most cases. I have done Alot of testing with Gp3 mod will under development and i'm sure this was the case, however my memory is not great. take with a grain of salt. perhaps this only apply's to open wheel cars where we see teams run ridiculously low pressures. most likely GT cars are much higher 28psi? and not effected.

    really, no Tyre model is perfect they all have their issues,this is why AC went through something like 11 Tyre model major modifications over its life span and although has decent is still lacks in some areas.
     
  14. Patrick Schumacher

    Patrick Schumacher Registered

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    I got a question not regarding the pressure of the tyres but I don't like to set up a new thread. Hope not a problem for the thread creator.

    Does anybody know what the perfect temperature for each type of tyre is, or the perfect working area?
    And does the wet ones gonna heat up above the average under dry conditions? I think it seems so but I'm not quite sure.

    Today I could observe how great the modell works. Wet tyres can be quickly cool down if you drive through wet areas beyond the dry racing line (when track is drying off). Races in which the conditions are changing gets a huge tactical impact by this. Perfect for endurance racing.
     
  15. Lazza

    Lazza Registered

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    @fireballR18 The optimum temperature, for momentary grip, is defined in the tyre files. If the mod maker doesn't tell you that you need to get it from the files - which means any locked mods (like most official ones) you can't see. So you're relying on that information being provided, or just judging it through experience driving it, or maybe conduct some tests and work it out (approximately) that way.

    Tyres generate heat through rolling and sliding, and are cooled down by the air, track (static track temp currently), and water cools them more. Decent wet tyres should be made to generate more heat and therefore will overheat more in dry conditions, but as far as I'm aware the tread depth isn't a factor here like in real life. Rubber does age with heat, but that's also the extent of it - wet tyres don't lose their sharp tread block edges and dissipate water less efficiently, but then aquaplaning isn't a thing either yet so there's no real dissipation happening. One of the gaps that still needs filling in rF2.
     
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  16. davehenrie

    davehenrie Registered

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    Generally you can find approximate ranges for items such as tires and brakes online...after some exhaustive searching... Somebody, about the time the GT3 pack came out, asked about brake temps and somebody found a webpage or chart that showed the best operating temps for steel, carbon or ceramic brakes. If you can find real world temps/pressures for tires, there is a good chance those are fairly accurate for the sim cars as well.
    Having said that, for most of the older tires in rF2, there was very little penalty from running serverly under-inflated tires. I don't know if the latest tires allow running at very low pressures without overheating.
     
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  17. Christos Segkounas

    Christos Segkounas Registered

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    Lower pressures give more grip, simple as.
    Now there's a limit where lowering the pressures further will cause the tire to deform during hard cornering and the handling deteriorate.
    There's a limit in RF2 in how low one can go so this is either not allowed or not simulated or both.
    IRL if you use too low tire pressures the handling will be shite but after a certain number of laps the tires will reach a temperature and the air will expand to a point where the tire will be able to maintain integrity.
    Provided you did not go like ridiculously low.
    Now on to temperatures, everyone will tell you that lower pressures are better for quali and higher for the race.
    I have not found that to be true in RF2 so far but hey, whatever,maybe I have just failed to notice it.
    So, tire pressures are related to not just the contact patch and temperature of tire but also it's integrity, same way as the hardness of a tire wall.
    So one need to spend time with their race car to find what works and what doesn't.
    Same with RF2, although here we are talking more about the sim in general, not each car specifically.
    I go with minimum tire pressures no matter the scenario, quali or sprint race or endurance, I find it's your driving that matters when it comes to tire temperature first and foremost.
     
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  18. Patrick Schumacher

    Patrick Schumacher Registered

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    Thanks guys for the answers.

    I will test it these days and perhaps I can figure out which are the threshold values also if there are different operation windows.

    This morning I tested the behaviour of the tires under excatly same conditions in dry and this was very impressive to see how the wet ones are heating up quickly and how much time you loose if you don't change the tires when surface is gonna dry off. The tyre modell is working really nice. I hope that I will face such conditions in my next online mp-race. I love this sim :)
     
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