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Cars Tyre sizes into Assetto Corsa

Discussion in 'Assetto Corsa Modding Discussions' started by ltcars, Jun 1, 2017.

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  1. ltcars

    ltcars

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    If I search tyre sizes at Google, I usually get a result like this:
    245/45R12 98

    However, AC asks for this:
    WIDTH=0.245 I know what to do for this but the rest...
    RADIUS=0.330
    RIM_RADIUS=0.254
     
  2. garyjpaterson

    garyjpaterson

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    Just a bit of maths, should be easy enough.

    245 - tread width (mm)
    45 - profile height (as a percentage of the above tread width)
    R12 - rim diameter (inches)

    You know the rim radius, thats 12 inches divided by 2, then converted to meters (google will do that for you). Though make that 13/2, because AC suggests adding 1 inch...

    Overall radius is rim radius plus 45% of 245.

    Or you can set up a wee formula in excel to do it for you :)

    WIDTH=0.245
    RADIUS=0.26265
    RIM_RADIUS=0.1651
     
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  3. ltcars

    ltcars

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    Thanks a lot
     
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  4. Stereo

    Stereo

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    You shouldn't include the extra inch in the overall radius though, since it represents the lip of the rim that extends out past the bead. I know your numbers don't, just worth being clear. The rim radius is used for popped tires to say where the car'll ride on its rims.
     
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  5. Willy Wale

    Willy Wale

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    Not sure if it matters in AC but the geometric radius of the wheel/tyre is different to the dynamic (wheel centre to ground) radius because the weight of the car squashes the tyre.
     
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  6. Stereo

    Stereo

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    Use the geometric radius in RADIUS=, then adjust the spring rate and spring rate change w/ pressure until the dynamic radius is ok.
     
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  7. garyjpaterson

    garyjpaterson

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    Yep I should've clarified that, i never even thought about it.