A peak on a tire?

Discussion in 'Car Modding' started by Damian Baldi, Mar 1, 2018.

  1. Damian Baldi

    Damian Baldi Registered

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    There is a peak on the rear tires. You can see the peak appears and disappears while the wheel spin. It's present all the time, it does not vary with temperature or wear. The peak is there and it warms more than the rest of the tire.

    How can that be possible? the nodes defines a section of the tire, then you have to define the amount of sections on the circunference, but that's all, there isn't values for each section.

    Could it be an error on the lookup table while running the tire on ttool?

    Any idea?


    [​IMG]
     
  2. Coutie

    Coutie Moderator

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  3. Jokeri

    Jokeri Registered

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    I've wondered the same thing.
    Can you see the issue in ttool's realtime section when you run it with the same load, speed, temp and pressure?
    Also, have you adjusted the lateral load distribution (I might remember the name wrong) and the rest of the modifiers?Ideally those modifyers should be 1
     
    Last edited: Mar 1, 2018
  4. Michael Borda

    Michael Borda Car Team

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    It can come about as a result of extrapolation.
    This is the default InclinationExtrapolation=1.0, it's defined under the [REALTIME] section.
    But for the last 16 months or so we've recorded tyres at a higher level of detail and extrapolation is rarely needed. You could probably set it to 0,0.
     
  5. Damian Baldi

    Damian Baldi Registered

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    ok I'll try that. It is a tire with 67 nodes and 200 sections.
     
  6. Damian Baldi

    Damian Baldi Registered

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    No luck. I see the same peak. I'll re run the tests on ttool and see what happens.

    a pic just to clear doubt about the shape
    [​IMG]
     
    Last edited: Mar 2, 2018
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  7. Damian Baldi

    Damian Baldi Registered

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    I got the same result after running the tire on ttool again. Playing a bit with variable "InclinationExtrapolation" the peak tend to dissapear if I use nevative values. What that means? The tire have too many nodes or sections?

    It's a tire with dimensions: 365x720 on a 19 inches rim. 59 nodes and 200 sections. I have another tire withe the exactly same dimensions with on a 18 inches rim, that doesn't have the peak.
     
  8. Damian Baldi

    Damian Baldi Registered

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    Well, I have the same problem (but worse) with a small tire for a small formula car. It looks like I'm using too many nodes (63 in this case). I'm doing the tire all over again using just 57 nodes this time. I'll see what happens.
     
  9. Damian Baldi

    Damian Baldi Registered

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    Well, 57 nodes was the solution for the small tire. Now it works well. I'll do the rear tire too to see what happens because it performs a bit odd.

    [​IMG]
     
  10. SPASKIS

    SPASKIS Registered

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    What does that graph represent?
    Under which type of load is it obtained?

    If purple colour represents contact patch the result would be clearly wrong. You would be getting black horizontal lines (non contact) in the middle of three of the four wheels.
     
  11. Damian Baldi

    Damian Baldi Registered

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    That's the contact patch of the 57 nodes tire. The tire with the problem has 63 nodes, and you can see on the image below, the peak and the narrowed contact patch on the front tires.

    [​IMG]
     

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