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.
     
  8. FakeThinkpad

    FakeThinkpad

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    Could someone help me out with this because Content Manager gives me a size that I don't agree with.

    I have a wheel size of 265/35/18

    Rim radius
    ((18+1) / 2) * 0,0254 = 0,2413

    Total Radius
    (18 / 2) * 0,0254 = 0,2286
    (265*0,35) / 1000 = 0,09275
    0,2286 + 0,09275 = 0,32185

    Yet when looking inside Content Manager it gives me 265/25/18?

    upload_2017-12-17_20-25-26.png
     
  9. ltcars

    ltcars

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    I think I had these too in the past, probably just a bug. I'm no expert though
     
  10. aphidgod

    aphidgod

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    For tire sizes, I cheat and go to tirerack.com and check the actual manufacturer spec on the tires in question. It's usually very close to, but not quite equal to, the mathematical result posted above.

    On the CM thing... I reported that as a bug a year ago. Was told it's working perfectly, even though it's not, so...
     
  11. FakeThinkpad

    FakeThinkpad

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    Thanks for the quick reply, sounds like I can disregard this as a bug of Content Manager then and not a formula error.

    Thanks again