CPM tyre warms up more at the sides

Discussion in 'Car Modding' started by dbaldi, Jun 3, 2017.

  1. dbaldi

    dbaldi Registered

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    I made new tyres with 57 nodes for front that works perfect, but the rear ones with 59 nodes warms at the sides more than in middle, even with different cambers or pressure.

    I tried changing the shape to be sure, but I have the same result. The shape is basically the one from the dev examples.

    It could be something with the materials, but there are so many that I can't try each one and see, because it will take ages.

    Any idea?

    The tyre is here https://www.dropbox.com/s/gek9oqhe5uverag/365x720R19goodyearR500_CPM.tgm?dl=0
     
  2. Michael Borda

    Michael Borda Car Team

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    Hi, sorry that it took me so long to get back to you. The overall shape and design look pretty much OK (though it's harder for me to tell from the .tgm than a source file). Most likely the tread is just slightly too flat and should have a bit more profile to it..
    But it depends on the overall behaviour, what should be done to the tyre to have a working solution. If you're happy with the stiffness, and overall characteristics of the tyre, other than it overheating a bit on the edges, I would suggest pulling the nodes around the effected area down to a slightly lower radius. This means smoothing out nodes 12-19 and pulling them slightly inward. If the tyre peak slip is too narrow or the tyre is in general too stiff, you could try softening the belt layer slightly, which will allow the air pressure to exert a greater influence on the actual shape of the tyre. I see you're using 160GPa, as the modulus for steel (some of my tyres did have that, yes), solid steel is usually 205GPa, stranded steel could usually be a bit lower than that. Around the 105-120GPa mark is what I've found to be sensible for most steel tyre cord types. With the radius change in that section of the tyre, I'm talking about ~1mm averaged across the 13-20 nodes. And transitioned with the other nodes to make sure there are no rough steps.
    The best way to verify that a tyre should be OK is using the QSA section of ttool and defining some typical / ideal conditions for the tyre to operate in, then look at the resulting pressure distribution of the tyre. I've taken an attempt at that, and you can see a fork shape in the screen capture to demonstrate the issue.

    See here https://www.dropbox.com/s/my1mz3n7mjzae44/GRAB_036.JPG?dl=0
     
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  3. dbaldi

    dbaldi Registered

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    Thanks for your answer Michael. What I try to change, beside the way the tyre warms, is the feeling and grip. Currently the tyre feels too stiff, and it lose the grip suddenly, there is not a good transition. You can feel the car trying to flex the tyre without sucess.

    I'll try your advices about the steel first, and then the shape.
     
  4. dbaldi

    dbaldi Registered

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    I made those changes and I have to say that the result is excellent, perfect warming and good feedback on the steering wheel.

    Thanks for your help.
     
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