TGM Tyre load sensivity

Discussion in 'Car Modding' started by Raintyre, Jan 14, 2015.

  1. Raintyre

    Raintyre Registered

    Joined:
    Jul 28, 2013
    Messages:
    226
    Likes Received:
    187
    Let's say we are developing a prototype car, with 900kg static weight plus 2500kg of downforce at high speed. These are realistic weight and downforce. However, when we go testing, high speed corner speed is too high compared to reality. There are corners where real cars speed is 250kph, while our virtual car can do it at flat out at 320kph.
    The problem is not excessive tyre grip, because slow corners performance is accurate. The problem is our tyres don't have enough load sensivity, as real tyres had. We would need more load sensivity to reduce a fraction of grip at high tyre load.
    My question is:

    How can I modify load sensivity on TGM files? which are the main parameters to do this? How can i set grip depending on tyre load?

    Thank you!
     
  2. Spinelli

    Spinelli Banned

    Joined:
    Jan 28, 2012
    Messages:
    5,290
    Likes Received:
    32
    I know in RF1 there's a line in the tyre file that's for how much drop-off in grip there is as you gain speed. It might still be there in the RF2 tyre file once it becomes generated from the

    Wish I could help you more.
     
  3. Slow Motion

    Slow Motion Registered

    Joined:
    Aug 14, 2012
    Messages:
    2,851
    Likes Received:
    6,736
    Welcome to the club! LoL

    You seem to be a step ahead... but the main question is: how / where did you find the TGM? Did you start by scratch generating the TGM or did you manage an existing one from an ISI car? For instance my problem with tires at the moment is the max speed vs. the TBC file (that is correct). So I need to decrease the max speed into the TGM file... but for sure, a TGM built for the specific tire of the specific car is the best solution.
    As you know the data you can change (without exaggerating) are those of the realtime section...

    EDIT: I forgot to add that, in case you find the way to reduce the corner speed reducing the lateral G, managing data into the realtime session, I hope you will share the discovery. Many thanks in advance.
     
    Last edited by a moderator: Jan 14, 2015
  4. Lazza

    Lazza Registered

    Joined:
    Oct 5, 2010
    Messages:
    12,345
    Likes Received:
    6,572
    You're probably looking for this (from the Tyretool_QuickStart_V3.pdf):

    RubberPressureSensitivityPower = Rubber contact pressure sensitivity (power, offset, nominal
    maximum, normalize (1=yes,2=no)). This adheres to the following formula,
    (BristleContactPressure+Offset)^Power, and if normalized (recommended) will provide a peak
    multiplier of 1.0 at 0 contact pressure.

    Set up a table of normal contact pressures and outputs from that equation in your favourite spreadsheet program and plug the existing values in, then have a play, and you should be able to get something like what you want.

    There's no parameter for this in the rF2 TGM files. I would guess that any such effect is done through the modelling of the tyre construction.
     
  5. Raintyre

    Raintyre Registered

    Joined:
    Jul 28, 2013
    Messages:
    226
    Likes Received:
    187
    Thank you very much Lazza and people who answered by private message.
    Geometric design of tyre and material properties should have an influence on load sensivity. However, it is very good to know there is also a direct parameter to modify this. I will try this 'RubberPressureSensitivityPower' for sure!


    >>>>>> For instance my problem with tires at the moment is the max speed vs. the TBC file (that is correct). So I need to decrease the max speed into the TGM file...

    What do you mean with 'max speed'? You mean top speed on straights? If you need more rolling resistance try with 'TemporaryBristleDamper' parameter. Perhaps there are other parameters that make influence on this, i still didn't try.
     

Share This Page