Remaining tyre % in HUD/Telemetry

Discussion in 'Car Modding' started by rigodon, Dec 18, 2019.

  1. rigodon

    rigodon Registered

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    Hi everybody,
    Recently, we were doing some testing in our league anout tyre degradation, and first, we created tyres with a wear degradation like this:

    DegradationPerWearFraction=(1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0.5)
    DegradationPerUnitHistory=(1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)

    That is, no thermal degradation, 50% of grip loss in last step of wear degradation. We found that we were in the last step of degradation when HUD / Telemetry was showing 50% for rear tyres and 33% for front tyres.

    Then, we switched the degradation values:

    DegradationPerWearFraction=(1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)
    DegradationPerUnitHistory=(1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0.5)

    No wear degradation, 50% grip loss on last step of thermal degradation. In this case, we were at last step of degradation when HUD / Telemetry was showing 3-4%. So our conclussion is that HUD/Telemetry is showing an average of 2 degradations and our tyres have too much wear degradation (or very little thermal degradation). It's the only valid explanation we found for a HUD showing 50% for a tyre and it being in last step of wear degradation. So, the rubber is completely worn but you still have a lot of way to go in thermal degradation.

    Has anything done any testing with this? Do you have a better explanation?

    Thanks in Advance
     
  2. mantasisg

    mantasisg Registered

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    Interesting, to me thats quite unexpected results ! Would be interesting if there is other explanation.

    It is strange if tire that is badly physically worn would still somehow have the thermal life in it. I remember that it was written that tread will never get thinner than thermal depth value, so is it a limitation of rF2 ? So if you'd wear down to 0.0001 (m?) of the tread, then you still would be fine if you haven't baked it ?

    However, I was able to get good results for wear with the sheared off rubber volumes and thermal activation and history steps values, of course working together with the rest of realtime parameters.

    I did one very little experiment with WLF start and step parameters. And I found it very weird. It seems like there is only tiny window where it works optimally. I tried reducing and increasing start value, and then increasing and reducing step value and it always resulted in way stronger tire wear. But in that little experiment I haven't been modest, I used twice larger or smaller values, probably it was too extreme, and probably the correct values are in much smaller window than is expected.
     
  3. Lazza

    Lazza Registered

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    Interesting analysis. It's true we don't know what the wear actually is (some average, or minimum, or weighted average, ...) and even if it were just wear we don't know if it would be the whole tyre or the part in contact. Actually you could probably eliminate the last with some slow testing, I've seen HUD and telemetry temperatures oscillating after a large lockup with slow rolling suggesting the current value represents the current contact patch or at least something less than the entire tyre.

    Thermal degradation could be severe at the contact patch and very low elsewhere (depending on use spread) so if it contributes it may not be straightforward.

    Ultimately, a single figure for wear isn't very realistic. F1's recent addition of a wear indicator to the official broadcast feed I find a gimmicky simplification for ill informed viewers. I'd be in favour of abandoning the live figure and substituting some wear measurements after the tyre is removed, as part of more proper tyre management, for a more realistic experience. But now I'm dreaming.
     
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  4. Raintyre

    Raintyre Registered

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    Thermal effects are not shown. Unfortunately we only see wear due to abrasion.

    If you test using low abrasion multipliers and fast thermal degradation you can lose all grip because of thermal degradation while indicators still say 100% tyre left.
     
    Last edited: Dec 21, 2019
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  5. Javibeza

    Javibeza Registered

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    Hi, I was working with Rigodon at these test. Our first test with wear was:

    DegradationPerWearFraction=(1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0.5)
    DegradationPerUnitHistory=(1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1)

    On this particular test, we should have noticed the lack of grip at 97% wear (3% at HUD and a minimum red bar shown on the HUD graph). However, we notice this at 33% of front tyres and 50% of rear tyres on the HUD.

    Does this mean that numbers and graphic bars shown on the built in status HUD are really not the real computed wear? If we can't see thermal effect on the HUD, then where does this number come from?


    [​IMG]

    Cheers.
     
    Last edited: Feb 13, 2020
  6. Lazza

    Lazza Registered

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    I haven't looked into the tyres in depth since quite early on, so I'm about to say something the TGM tools (spreadsheet especially) may contradict - but is it possible to wear through the outer tread, and hit that wear degradation number, while still having quite a lot of overall tread (50%, 33%...) left?
     
  7. mantasisg

    mantasisg Registered

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    I am glad I come back to read this. And immediately saving few hours wasted of testing.

    Edit:

    It is a big shame really. Recently I set goal to make a wet tire that would wear less than dry tire in wet, and more than dry tire in dry. Obviously.

    It is a bit unfortunate that thermal degradation is not represented in tire app as it seems the only way to make it work, although maybe it is more realistic, although knowing abrassive wear real time isn't realistic either.

    By the way, I discovered one ,ore new thing to me. Looks like abrassive wear is even larger in the wet. Which to me seems like it shouldn't be so, but perhaps I am wrong ? So because of that it only makes sense to have wet tire that in terms of abrassion wear would be same as dry tire, because otherwise wet tire would loose advantage over dry tire in the wet. And it is not ideal IMo, because naturally wet tire is softer, and I'd expect it to wear from abrassion in the dry more, as well as to have more thermal degradation. And I also would expect dry tire to have minimum wear in wet, but poor performance. I suppose greater tire wear in the wet could be justified by the fact that there is more sliding, however I'd expect sliding itself over wet surface to shear less rubber off because of less friction, the surface is essentially lubricated. Another rF2 limitation ? Or I get something wrong ?
     
    Last edited: Jun 24, 2020
  8. Lazza

    Lazza Registered

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    Any visibility would be a bit weird, yes.

    But from a modding point of view, we know thermal degradation is a function of running overtemp. You could set up a measurement of that (for example, sum the excess temperatures over time in i2Pro) and calibrate the results with a very sharp dropoff at a certain step. Then you have a rough guide for setting and verifying thermal deg for different tyres.

    Abrasion is a whole other matter, I haven't experimented enough yet to contribute to a discussion.
     
  9. Raintyre

    Raintyre Registered

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    Yes, very often abrasive wear is larger in the wet, because there is usually more sliding... I agree, the overall result is not realistic. And the result should be the only important thing.
    The good news are that you possibly can arrive to realistic results using abrasion wear curve and heating rate tweakers. (Could we also have tweakers for optimum pressures, please? That would be great, thanks).

    Make your tyres more heat sensitive depending on wetness, so that they reach 200ºC in the dry and only 40ºC in the wet. And then multiply left side of your abrasion curve. Left side will mainly be applied when tyres are very hot, while right side will be applied only when cold. This way you can make your rain tyres destroy in the dry while they are stable in the wet.

    Here you can see a example for two different wetness levels. Second run starts on 8:40
     
    Last edited: Jun 25, 2020
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  10. mantasisg

    mantasisg Registered

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    Thanks a lot ! That is very interesting, I'll come back to tell how it went, hope to find time soon. The left/right side of the curve means left/right side of the AbrasionVolumePerUnitEnergy line ?

    +1 on optimum pressure tweaker, I wonder what stops it
     
  11. Raintyre

    Raintyre Registered

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    Yes, that is it
     
    Last edited: Jun 26, 2020
  12. mantasisg

    mantasisg Registered

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    Just coming back to report that it works as you described, thanks again :)
     
  13. mantasisg

    mantasisg Registered

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    @Raintyre Been working on balancing abrassive wear curve for few tires. I can't help but it seems like it also somehow directly influences grip. Seems like if the faster abrassive shear tears of rubber, the harder it is to keep car under control when it slips. It isn't obvious when doing subtle tweaks, but as soon as I got wear way too fast, it was very hard to keep car in control. I am not sure if it directly influences grip, or if it influences temperatures or something which then could be influencing grip. Could you confirm this ?

    It is also good news, might then get less wear for wet track, and get better handling :) I think, still need to do many wet track test drives, but if this works, they are going to be a lot moe enjoyable and productive.
     
  14. Raintyre

    Raintyre Registered

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    I am not sure, i didn't observe that. But if you put a extremely high wear rate then it makes sense that you notice the loss of grip even on the same corner or same slide!
     
    Last edited: Jul 27, 2020
  15. mantasisg

    mantasisg Registered

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    Yes, basically it feels like extreme loss of grip when during the "average" slide, tire wears more than one percent. But it feels then like it is more eager to slide too.

    Another thing that I noticed was that when I put extreme high wear on the high temps side of curve, the flatspots rattling FFB effect appeared, and a lot of it :D well it makes sense lol
     

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