Tyre force components

The term “Tyre Force” generally means the total force exerted by the ground on the tyre. This force has lateral and longitudinal components for a driven tyre as shown in the diagram. These components can be further resolved into the central and tractive forces. It is essentially the central force that provides the centripetal acceleration of the car. It is the tractive force that determines whether the car rounds the corner at constant speed or not. The distinction between these forces their magnitude and vectors are often overlooked by students of vehicle dynamics. As we will see later their importance is vital when related to the vehicle in motion. Three situations are shown below:

  • Combined driving and cornering
  • Pure cornering
  • Combined braking and cornering


Combined Driving and Cornering:
The lateral and longitudinal forces resolve to a resultant tyre force, which in turn has components producing the central and tyre tractive forces.

Tyre force components - White-Smoke


Pure Cornering:
The tyre force now equals the lateral force. This force has components producing the central and tyre drag forces.

Tyre force components - White-Smoke


Combined Braking and Cornering:
The lateral and longitudinal forces resolve to a resultant tyre force, which in turn has components producing the central and tyre drag forces.

Tyre force components - White-Smoke

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