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Two cars turning into a corner.

  1. May 28, 2015 #1
    Okay so my friends and I had a debate on a topic which was regarding the cornering of the car.
    So the situation is this
    The two cars are the same, and the corner they turn into is the same. Considering that the two cars follow the same line in taking the turn, which car would come out in a faster time given that only the size of the wheel (15, 17 inch) . The speed that the car turns in is the same, the overall weight is the same, the line the car turns in is the same.
    So is it true that the car with bigger tyres will take less time to come out of the bend.
    No external forces are acting on the car except downward force.
    A hypothetical scenario. Please explain! Thanks
  2. jcsd
  3. May 28, 2015 #2


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    Staff: Mentor

    If the speed is the same, and they follow the same path, then how can there be any difference in cornering time?
  4. May 29, 2015 #3


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    Gold Member

    I agree with Drakkith. Incidentally, there is a second external force on the car - centripetal force acting towards the centre of the curve.
  5. May 29, 2015 #4
    Depends on the surface.

    Assuming identical vehicles the overall diameter of the wheels must be the same, therefore, the car with the larger wheels will have lower aspect ratio tires. On a smooth surface the lower aspect ratio tires will deform less, therefore they will have more a more consistent contact patch with the road. Assuming the car / suspension was properly designed to begin with a more consistent contact patch will stay closer to optimum then a less consistent patch. Therefore, the car with the larger wheels will have better traction have have to slow down less for the corner.

    On an uneven surface, such as off road, you want the tire to be able to deform to match the contours of the surface. The lower aspect ratio tires associated with the smaller wheels will have more room to deform. This will only occur if the pressure is low enough to allow significant deformation, but again, I am assuming the vehicle is set up properly.

    So assuming the vehicle is set up properly for the wheels and surface condition, the larger wheels/thinner tires will corner better on a smooth surface, the smaller wheels/thicker tires will corner better on an uneven surface.
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