[Uniformity] Conicity

Conicity is directly related to steering pull. A tire that has high conicity will give a vehicle high steering pull, a strong pull in either direction. The ASTEC® machine will measure the degree, or amount of steering pull.


The word conicity is derived from the word cone. Conicity refers to when a tire physically behaves as if it were shaped like a cone. If a tire has conicity, it would mean that a lateral force is generated in the same direction no matter which way it was rotated.


Conicity is defined as lateral shift clockwise plus lateral shift counterclockwise divided by 2.


Conicity = [(LScw+LSccw) / 2].


The Primary cause is an off-center belt.