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What is Tire Cornering Stiffness?

Posted: Tue Oct 20, 2009 11:03 pm
by brian
Q: What is Tire Cornering Stiffness?
A: When a tire is orientated at an angle not equal to its direction of motion, a side force acts perpendicular to the plane of the wheel. The relation is nearly linear for small slip angles. The relationship that defines side force as a function of slip angle makes use of the tire cornering stiffness.
The SAE book by Gillespie, Fundamentals of Vehicle Dynamics p 347-355, indicates that
  • for bias-ply tires cornering stiffnesses are approx 12 % of the load on the tire (with a range of approx. 8%-18%) and
  • radial tires cornering stiffnesses are approximately 15% of the load on the tire (with a range of approx. 11%-19%).
  • There are also discussions in the book about the effects of inflation pressure
    • (normally increasing the inflation pressure increases the cornering stiffness),
  • tire size and width
    • (larger size and width normally produces greater cornering stiffnesses),
  • tread design and aspect-ratio
    • (aspect-ratio=ratio of section height to section width, common vehicles ranged from 0.78 to 0.70,
  • recent trends towards lower-aspect-ratio performance tires (0.60 and lower) on cars may produce cornering coefficients in the range of as much as 25% to 30% of the load on the tire).
Please refer to that book for further information and references.
For additional discussion please see the msmac input manual discussion: