Ideal Tire pressures and Temp splits

Discussion in 'General Discussion' started by Michael Havlena, Jul 19, 2020.

  1. Michael Havlena

    Michael Havlena New Member

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    Hi Guys,

    Are there any ideal tire pressures when hot? Obviously, this will depend on the car, but just as a general rule would like to know what people typically aim to get on track...

    Also, are we still recommending 5 to 7 deg C tire temp split? (camber adjustment)

    Thanks guys!
     
  2. Maskerader

    Maskerader Well-Known Member

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    85 degrees is the optimal temperature (it's fixed to this value when you do a leaderboard challenge or test drive a car). On the car setup screen you find some info and tips when you hover over a setting, and it says that you should aim at 5-10 degrees difference.

    I don't know about pressure though, I guess you should choose one that helps you be closer to optimal temps.
     
  3. Michael Havlena

    Michael Havlena New Member

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    Ok thanks. Interesting info as the overall tire temp is not provided in the setup pages, only the split temps. I know you can find the overall tire temps in the main HUD display, just not available in the setup pages, which would have been helpful. Based on my quick verification, to achieve 85 deg, one would need to set tire pressure to approx 27.5 to 28.0 psi, which is bang-on with ACC requirements....Oh and one other thing, the tire pressure that we set is HOT pressure and not COLD pressure. Please advise that this is indeed the case. Thanks so much!...;)
     
  4. Alex Hodgkinson

    Alex Hodgkinson KW Studios Developer

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    The in-car dash temperatures show the hottest part of the tyre. So if you have 80/82/88, the dash will show 88.

    Adjust the tyre pressures to equalise the temperature spread. For example you have the split above (80/82/88) you would want to slightly increase the tyre pressure until the middle temperature is equal to the average of the inside and outside temperatures - or 84 here.

    The pressures in the garage set what is applied to the car the moment you press drive. With a GT3 which uses tyre warmers, those are effectively hot pressures. Whereas with the Porsche GT3 Cup which does not have tyre warmers, you're setting cold pressures.
     
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  5. Maskerader

    Maskerader Well-Known Member

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    Why? I always thought it shows an average temp.
     
  6. Maarten

    Maarten Member

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    Because your average can look great, but you're actually killing the tire. (cold outer, hot inner)
     
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  7. Maskerader

    Maskerader Well-Known Member

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    Why would it matter at this point? Temp split is something you address while setting up the car, and when doing so you have access to all temps anyway. If you made a mistake and went to the race, you can't do anything at that point. And if you try to reduce the load on that tire and reduce the temps, you'll end up with even worse temps anyway.

    If you had, for example, 75-85-95 (is 95 killing? I wouldn't say so personally...) you get something like 70-78-90 because tire pressure drops too and so does middle temp. Your temps still suck big time and now they are even farther from the optimum.

    I mean, if you know your car and its setup, you can work with any temperature displayed. If you don't know your car, the average or the middle temp is probably more meaningful because it's closer to the overall state of your tire. So by default I'd expect the average or the middle to be shown, not the highest. For me it's just an unnecessary confusion.

    But if this is what they do in real life, I'm okay with that.
     
    Last edited: Jul 20, 2020
  8. Nico Kunze

    Nico Kunze Well-Known Member

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    While were on tire temps, if the ideal temperature for a certain car is say 85 degrees, should i aim for the middle of the tire to have 85 degrees or the inside or the outside?
    And im still struggling to really change the setup in a way that affects the tire temps (especially when theyre too hot). Would appreciate a couple tips by anybody having success with that :)
     
  9. Maarten

    Maarten Member

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    I'm not an expert by any means, so take this with a grain of salt. The hottest part of the tire is the part that's being worked the most. This is therefore the most critical part of the tire in regards to wear and road contact. So this is the part which is most important to get information about.
     
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  10. majuh

    majuh Well-Known Member

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    It's almost impossible in RaceRoom, you just have to deal with it.
     
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  11. Vale

    Vale Well-Known Member

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    Reduce steering lock.
     
  12. Zziggy

    Zziggy Well-Known Member

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    My idea would be to avoid understeer and drive with minimum steering input, but how this is done, I don´t know ... :confused:
     
  13. Alex Hodgkinson

    Alex Hodgkinson KW Studios Developer

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    It's more important to average out the temperatures across the surface of the tyre. The total temperature of each tyre is a function of many factors you don't have control of. Thus you should focus most on optimising tyre surface usage per-tyre rather than trying to think about overall temperatures.
    This is where tyre temperature comes from;

    - Lateral tyre force
    - Longitudinal tyre force
    - Slip angle
    - Slip ratio
    - Speed
    - Thermal conductivity between tyre and air
    - Thermal conductivity between tyre and road
    - Track temperature

    Most importantly, if you work to optimise the temperature spread across each tyre's surface, the variation you see when comparing tyres across the axle or front-to-rear will be reduced.

    If there are still issues with under or over-temperature tyres, softening the springs at that end of the car will reduce the forces the tyre is subject to and reduce temperatures. Increasing spring stiffness will have the opposite effect.
     
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  14. Nico Kunze

    Nico Kunze Well-Known Member

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    Thats usually the first thing i try but most of the time without any significant results
    I see, guess thats what ill go by then (although going back to the setup screen and seeing a red tire begging me to change something will probably still get me thinking :D)
    But thanks for the answer :)
     
  15. Vale

    Vale Well-Known Member

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    If fronts are overheating then reducing steering angle, putting brake balance back and reducing brake pressure may help in fixed setup rooms. For rears, increasing TC on tc enabled cars can help and trying to appply power more carefully so as not to slide or wheelspin.

    It´s a pity we can´t mix tyre compounds per axle or wheel as that would solve the issue of tyre wear and is what would be done in real life.

    If setup is adjustable then adjusting camber, roll bars, dampers and toe-in can also help a little but there are limits and these will affect handling in other ways so you might have an ill handling car.
     
  16. Alex Hodgkinson

    Alex Hodgkinson KW Studios Developer

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    Ah but you can on some cars which have this enabled. Try the Porsche GTE.
     
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