Tire modeling help

Discussion in 'Car Modding' started by thoraxe, May 15, 2020.

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  1. thoraxe

    thoraxe Registered

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    Short of having a connection to engineers that work at the tire company, what's the general process for trying to model a tire?

    I am trying to model my real-world vehicle and am trying to wrap my head around the tire tab in the physics spreadsheet. I have a loose tire and I have tires mounted on my wheels, so measurements are possible. But a lot of these things are not really something I can easily measure myself without highly specialized equipment.

    This is the tire I'm running:
    https://www.nankang.eu/index.php?id_product=64&controller=product

    I have a contact at Nankang that I am trying to reach to actually get me in touch with engineers. I realize that some of the information is likely proprietary and they may ask me to keep it confidential, so I may end up having to encrypt the tire data.

    But, generally speaking, given a tire laying on your garage floor, what would be the process for building a model / getting all the required data to fill out the spreadsheet?
     
  2. mantasisg

    mantasisg Registered

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    Sorry I can not offer help to your exact needs.

    But appart from tire spreadsheet, + maybe also apart working with ttool. You could possibly use some existing available as somilar as possible rF2 tire and just maybe tweak its dimentions with these tools http://meetme.bplaced.net/rF2_onlineTools/ and after that adjust [real time] values to better match real tire behavior. So thats just for beginning. But it would be quite something already.

    Can't give any advice for advanced stuff - spreadsheet, ttool, deep data....

    By the way, I highly doubt that you could get access to s397 encryption, but it is nice try haha, good luck on that.
     
  3. Raintyre

    Raintyre Registered

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    Perhaps this opinion is useful for you?
     
  4. thoraxe

    thoraxe Registered

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    I didn't think that encrypting the content required "access" to S397 encryption, but rather was done when using the MAS tool to create the package/bundle. But I haven't looked in a minute. Thanks for the tooling suggestions!
     
  5. thoraxe

    thoraxe Registered

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    It's super useful, however none of that data is "stuff I got" from Nankang so far. Squishiness (tire stiffness) is one that I'm looking for.

    As an example, here's what the spreadsheet is looking for:

    SpringRate B [N/m]
    SpringRate kPa [N/m]
    Spring Rate [N/m]
    Static Load
    Deflection [m]
    RR Drag
    RR Toque [Nm]
    Coeff Rolling Resist.
    RollRes TBC
    Damper [N/m/s]
    DampingRatio
    Tyre only cDR
    FrictionTorque [Nm]
    Friction Drag

    I have approximately zero of these values :)

    The basics of the tire spec are things that I have or can (relatively) easily measure.

    I know that I am not going to get perfect numbers. But right now I basically have no numbers and am looking for a path forward.
     
  6. thoraxe

    thoraxe Registered

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    Looking at https://docs.studio-397.com/developers-guide/cars/car-physics/tyre-database and the properties published for the tire I have, the 27/65-18x10.5 from the rF2 database is "close" in terms of size. But that's the TGM, and not the TBC. That being all said, I'm concerned that even a hardness 9 slick is probably too "soft" compared to the semi-slick that this tire is.

    So, I'd even be open to suggestions for how to approximate the tire I've got...
     
  7. Jokeri

    Jokeri Registered

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    -Measure the weight of the tyre
    -Model or estimate the land to sea ratio of the tyre surface
    -Measure the tyre radius with zero pressure
    -Measure the tyre radius with zero pressure and different amounts of load
    -Scan the shape of the tyre with zero pressure if you can
    -Cut the tyre to see how the plys are spaced and how they are angled or ask you contact
    -Cut the tyre to measure the diameter of the plys or ask your contact
    -Measure the physical properties of the plys and belts or ask your contact
     
    Last edited: May 15, 2020
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  8. Emery

    Emery Registered

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    If the Nanking tire is DOT certified, then the sidewall will tell you how many plies & what materials the plies are made of. You'll have to cut it apart to get the thickness, spacing, & angles of the plies. Together with the thickness of the rubber at each node, these are needed for the TGM and then you get into the rest of the properties. Fortunately, you've got tires in hand, so you'll be able to measure all these parameters...

    Some of the other things, for the spreadsheet, you're probably going to have to punt and see what values can be found in tires from other mods.
     
  9. Lazza

    Lazza Registered

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    The TBC is basically not used for player physics (radius has to be correct, perhaps something else I can't quite remember as well, but maybe not...), and is the old rF1 tyre model. It's really not a consideration in terms of what you're looking at in this thread, you can take an existing TBC and just tweak a few values to approximate your (later) TGM files and then adjust as needed for AI performance.

    Read through the development blog on the S397 site, unfortunately the comments sections were lost when the site transitioned a couple of years back but it goes over the process.
     
  10. thoraxe

    thoraxe Registered

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    @Lazza the manufacturer is providing information, but it's slow, and they've asked me to keep it confidential, so I can't share it back.

    Oh... I just opened the TGM generator. And it sounds like I need to be using that. I will see what I can figure out. It looks pretty nuts, so I'll probably punt and just use an existing tire for a while.
     

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