Tire heat mostly on the inside now?

Discussion in 'General Discussion' started by Amanda Santini, May 20, 2019.

  1. Amanda Santini

    Amanda Santini Registered

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    Now onto another issue: do you guys lose tire temp too rapidly?
    Because with quite a few cars, my tires come out of corners at e.g. 87ºC, then after just a few seconds they're at 65ºC, so instead of pink they're now blue or too cold.

    This happens even on 30ºC ambient temp and medium tires at their minimum pressure.
     
  2. Lazza

    Lazza Registered

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    Define 'too rapidly'.

    The temps you see in game are surface temperatures, and they change very quickly. I don't know whether anyone can provide real data on this (thermal images usually lack range info, so you can't tell if white -> black represents 10° or 50° change), but I've heard 130° mentioned in F1 commentary for cornering temperatures, and I've seen various places (though not an official source) give working ranges of tyres going from around 100° for the softer compounds to 145° for the harder. I think it's safe to assume the temperatures down the straights are much cooler than that.

    Bear in mind when you're driving out of a corner at 150kph the tyre is effectively being hit by winds of 150kph. But that's only an average: the top of the tyre (let's assume open-wheeler) is actually travelling forward at 300kph, while the bottom of the tyre about to touch the road is just about 0kph. So rubber at 100° is spending its time in contact with the road surface at maybe 45°, or in contact with air temperature 25° at speeds constantly varying between 0kph and 300kph (at that 'medium' corner exit speed). That all produces temperature loss at the surface, and on a straight there isn't a lot of friction to combat it.

    The deeper rubber is still flexing even down the straights, and is obviously shielded from the wind and direct track contact by the outer rubber, so it doesn't vary as much. Same is true in the corners where the deeper rubber isn't immediately affected by friction whereas the surface will heat very quickly.


    This all suggests a large variation would be expected. Since you rely on tyre grip mainly in the corners, it is logical that you would have them running 'cold' down the straights so that when you work them in the corners they heat up to the optimal range; no point running them hot down the straights and overheating when you want them to work for you.

    So: how quickly should surface temperatures fall? Anyone have a reliable source?


    Note: I don't think rF2 has parameters governing how much airflow a tyre gets in a particular car, which would seem to have some influence on tyre temperature behaviour. Recently in MotoGP for example, Ducati introduced a small scoop in front of their rear tyre which likely was done for aerodynamic gain, but they're allowed to keep it because they showed it gave them 7° worth of cooling (and is therefore allowed under the rules, whereas pure aerodynamic devices in that area are not). I would guess the temperature delta is instead massaged into the rF2 tyre files, but if tyres are always used in similar types of cars it probably has little detrimental effect in the game. Still, this would be a nice addition for a sim, along with brake -> wheel -> tyre heat transfer. But I digress.
     
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  3. David O'Reilly

    David O'Reilly Registered

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    I haven't checked it recently but a few builds ago the airflow was the only cooling effect, IE there was no radiated heat loss from a tyre.
    I discovered this by accident, did a wheelspin and stopped. Tyres stayed very hot till I moved again.
     
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  4. Lazza

    Lazza Registered

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    Worth testing, but I don't think I've seen this. @UsedMomo liked your post so perhaps had had the same happen?
     
  5. davehenrie

    davehenrie Registered

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    Could some of the heat dissipation be due to rolling transfer to asphalt? (in the old days that was more effective than air cooling)
     
  6. Lazza

    Lazza Registered

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    @davidporeilly Just did some testing (albeit in the Eve F3, but shouldn't matter) and temps definitely do drop at rest, just slow enough to seem static at low deltas (~40C takes a second or three to move; 180C is dropping noticeably).

    Something perhaps more interesting is the reported temperature, in the game and via telemetry. I had noticed previously that if you come to a skidding stop and then slowly roll you can see the tyre temps fluctuate, suggesting that instead of reporting the tyre temperature as a complete average it's only showing part of the tyre. I just played around with this a bit more and after spinning up the rears (>200C), sitting still until the temperature drops to around 160 (just under 20 seconds later), and then slowly moving, the temperature is fluctuating as it reduces (and reduces more quickly than at rest). It looks much too fast to be showing either a hotter patch or a cooler patch of the tyre though - it's fluctuating several times faster than the tyres should be rotating (about about 0.45m instead of every ~2m). I'm not sure what that means about how temps are reported or how temperatures are stored/calculated for tyres, but I found it interesting.
     
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