Contact Patch
Where the portion of a vehicle’s tire comes in contact with the road surface is called the contact patch. It is important to recognize that the contact patch is the only connection between the road and the vehicle.
Characteristics
The size of the contact patch largely depends on two factors:
- Tire Load: Higher load on the tire results in a larger contact patch.
- Tire Pressure: Higher tire pressure results in a smaller contact patch.
However, these two properties are not linearly proportional to the area of the contact. For example, doubling the tire load or pressure does not usually result in doubling of the contact patch area. This does make sense, considering that the contact patch area will always be limited by the geometry of the tire.
The size of the contact patch is roughly equal to the weight of the car divided by the compressed air pressure inside the tires. This is not a perfect equation, however, since the size of the contact patch is also influenced by the stiffness of the sidewalls and other physical properties of the tire.
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