I don't think I follow. The general idea is that negative camber will give oversteer. Which is why it's the only adjustment you can make in GT4 on camber.
No the general idea of negative camber (or camber as a subject in its own right) is not that it will give you under or oversteer (it can be used to trim these characteristics however), rather that its used to control the position of the tyres contact patch relativeto the road surface during cornering. Exactly how it will effect this relationship will depend on a wide range of factors, including tyre size (particularly sidewall ratio ), roll-angle, suspension type and geometry, etc.
The following is taken from my GT tuning guide (link in my sig) on Camber tuning, most of which relates to real-world camber set-up (admitidly on a much more basic level) and should help explain.
Camber Settings
Camber is the angle of the wheel relative to vertical, as viewed from the front or the rear of the car. If the wheel leans in towards the chassis, it has negative camber; if it leans away from the car, it has positive camber.
GT4 only uses negative camber, as positive camber is very rarely used on cars set up for racing or track work, its function being limited to the set-up of production road cars.
The principal purpose of setting camber is to ensure that the maximum area of the tyres contact patch is used during cornering. As a car corners the suspension and movement of the tyre cause the contact patch to change size as the car rolls.
The downside is that with negative camber the contact patch is minimised when the car is not turning which can reduce straight-line traction for the driven wheels and stability. Also setting too extreme a camber value may mean that the full contact patch of the tyre is never used even during hard cornering.
As camber settings will affect the level of grip at the front and back of the car, it can be used to trim under and over steer if required. Personally I would rarely do this as my main aim with camber is simply to maximise traction while cornering. The rest of the suspension settings can be used to help control under and over steer characteristics. This is however a personal choice based upon the tuners driving style and sometimes the demands of a particular car.
Setting camber is something of a black art as it is only possible to estimate the effect and only through testing will the correct setting be discovered.
Overall Camber Settings
Front Camber
Advantages
- Increases cornering grip for the front tyres up to a point after which grip will reduce.
- Reduces understeer.
Disadvantages
- Reduces straight-line traction (for FWD/4WD cars) and stability.
- Braking distance increases and stability reduced.
- Very high settings can reduce initial turn-in.
Rear Camber
Advantages
- Increases cornering grip for the rear tyres up to a point, after which grip will reduce.
- Reduces Oversteer.
Disadvantages
- Reduces straight line traction (for RWD/MR/4WD/RR cars) and stability.
- High settings can increase oversteer as the contact patch is distorted.
- Less warning when the limited is reached.
The above has been tested over hundereds of hours and a huge range of cars in GT4 and is an accurate reflection of the effects of camber changes. It is however, as I mentioned above, a gross simplification of how camber works in the real world.
The following is taken from ART's website and gives a (slightly) more in-depth look at camber.
WHAT IS CAMBER?
Camber is the angle of the wheel relative to vertical, as viewed from the front or the rear of the car. If the wheel leans in towards the chassis, it has negative camber; if it leans away from the car, it has positive camber (see next page). The cornering force that a tire can develop is highly dependent on its angle relative to the road surface, and so wheel camber has a major effect on the road holding of a car. It's interesting to note that a tire develops its maximum cornering force at a small negative camber angle, typically around neg. 1/2 degree. This fact is due to the contribution of camber thrust, which is an additional lateral force generated by elastic deformation as the tread rubber pulls through the tire/road interface (the contact patch).
To optimize a tire's performance in a corner, it's the job of the suspension designer to assume that the tire is always operating at a slightly negative camber angle. This can be a very difficult task, since, as the chassis rolls in a corner, the suspension must deflect vertically some distance. Since the wheel is connected to the chassis by several links which must rotate to allow for the wheel deflection, the wheel can be subject to large camber changes as the suspension moves up and down. For this reason, the more the wheel must deflect from its static position, the more difficult it is to maintain an ideal camber angle. Thus, the relatively large wheel travel and soft roll stiffness needed to provide a smooth ride in passenger cars presents a difficult design challenge, while the small wheel travel and high roll stiffness inherent in racing cars reduces the engineer's headaches.
It's important to draw the distinction between camber relative to the road, and camber relative to the chassis. To maintain the ideal camber relative to the road, the suspension must be designed so that wheel camber relative to the chassis becomes increasingly negative as the suspension deflects upward. The illustration on the bottom of page 46 shows why this is so. If the suspension were designed so as to maintain no camber change relative to the chassis, then body roll would induce positive camber of the wheel relative to the road. Thus, to negate the effect of body roll, the suspension must be designed so that it pulls in the top of the wheel (i.e., gains negative camber) as it is deflected upwards.
While maintaining the ideal camber angle throughout the suspension travel assures that the tire is operating at peak efficiency, designers often configure the front suspensions of passenger cars so that the wheels gain positive camber as they are deflected upward. The purpose of such a design is to reduce the cornering power of the front end relative to the rear end, so that the car will understeer in steadily greater amounts up to the limit of adhesion. Understeer is inherently a much safer and more stable condition than oversteer, and thus is preferable for cars intended for the public.
Since most independent suspensions are designed so that the camber varies as the wheel moves up and down relative to the chassis, the camber angle that we set when we align the car is not typically what is seen when the car is in a corner. Nevertheless, it's really the only reference we have to make camber adjustments. For competition, it's necessary to set the camber under the static condition, test the car, then alter the static setting in the direction that is indicated by the test results.
The best way to determine the proper camber for competition is to measure the temperature profile across the tire tread immediately after completing some hot laps. In general, it's desirable to have the inboard edge of the tire slightly hotter than the outboard edge. However, it's far more important to ensure that the tire is up to its proper operating temperature than it is to have an "ideal" temperature profile. Thus, it may be advantageous to run extra negative camber to work the tires up to temperature.
(TOP LEFT) Positive camber: The bottoms of the wheels are closer together than the tops. (TOP RIGHT) Negative camber: The tops of the wheels are closer together than the bottoms. (CENTER) When a suspension does not gain camber during deflection, this causes a severe positive camber condition when the car leans during cornering. This can cause funky handling. (BOTTOM) Fight the funk: A suspension that gains camber during deflection will compensate for body roll. Tuning dynamic camber angles is one of the black arts of suspension tuning.
The full article (covering Caster (not found in GT4) and toe) can be found here
http://www.advancedracing.com/chassissetup.php
And should you wish I can recomend further, far more in-depth, information sources.
Regards
Scaff
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