What Is Camber Gain?
Camber gain is the change in camber angle per amount of vertical displacement of the wheel. The most common situation is that camber will become more negative if the wheel is moved vertically upwards. Likewise, the wheel camber will become more positive if the wheel is moved vertically downwards.
Camber gain is controlled and limited by an area of geometry called the front view swing arm.
The Purpose Of Camber Gain
Camber gain is a useful tool especially within motorsport. During cornering, there is a lateral load transfer across the car. This causes the car to roll and would cause a car with zero static camber to roll off the contact patch and reduce cornering grip.
Camber gain allows the tyre to increase the camber as the vehicle rolls, particularly in a car with a soft suspension set up. This means that the contact patch of the tyre can remain in full contact with the track. This can be controlled by setting static camber.
The perfect balance between cornering grip and braking grip is key in motorsport. This is where camber gain must be controlled. Under braking conditions, the suspension will operate into bump on the front similar to the outside wheel during cornering.
This would make the tyre gain camber and would reduce braking force through the tyre. Therefore the geometry of the suspension must find a point of compromise that gives enough camber gain during cornering to increase grip but also gives little enough camber gain during braking conditions to maximise contact patch and grip.
Camber Gain Dynamics
Camber gain, also known as camber change rate, is a function of the front view swing arm (fvsa) length. If you replace the control arms of the suspension with a single link that ran from the knuckle to the instantaneous centre, the amount of camber change that was achieved per inch of ride travel would be camber change in degrees per inch.
This is an entirely different function from static camber settings or alignment. The camber change rate is controlled by the rate of change of the front view swing arm.