I found a good source that may explain this. The source (listed below) also has great explanations of how the transmission, differential, and brake balancing works as well.
Ride Height
Generally, you want as low a ride height as possible without bottoming out the suspension on rough roads and under heavy weight transfer. However, balancing the front and rear ride height can let you play with your vehicle's center of gravity. A higher ride height in the rear will shift the car's center of gravity forward, which may help front tire grip. The opposite is also true.
Ride Height: Lower<===>Higher
Spring Rate
Most vehicles come from the factory with fairly soft springs made to deal with rough public roads. On the track, however, the range of lumpy road surfaces is much narrower. The generally smoother track surfaces make suspension stiffening a very helpful adjustment in the corners. However, like all things in tuning, too much of anything will negatively impact your lap times.
Stiffer suspension will better control suspension travel and the always-changing nature of your wheel camber. By holding wheel camber more constant, you can effectively keep the tires flat against the pavement for improved grip. Too much suspension travel will cause the camber angle to change—since suspension does not travel straight upward, but rather in an arc—which will result in vastly different levels of grip depending on the weight balance of the vehicle at any given moment.
Though as we mentioned, too much suspension stiffness can be a bad thing. Too-stiff suspension will not have the travel necessary to properly deal with imperfections in the road surface. Slight bumps in the road will then cause the tires to skip and lose traction. As such, stiffening the front suspension too much can cause understeer, while stiffening the rear suspension too much can cause oversteer. Conversely, you can reduce understeer and oversteer by softening the front and rear suspension, respectively.
Spring Rate: Softer<===>Harder
Damping
While spring stiffness determines how much travel is in the suspension, dampers, also known as shocks, control the rate at which a vehicle's springs oscillate. Picture hitting a large bump at high speed in a standard road-going vehicle. After the bump, the car's suspension will continue to oscillate, bouncing up and down as the springs settle back down to their normal state. While this oscillation is good for driver comfort on public roads, it's not so desirable on the race track. The fluctuating weight balance during such oscillation can make tire grip unsteady, fluctuating with the suspension travel.
Stiffer shocks will control the oscillation of the suspension for a steadier weight balance. As well, stiffer springs will increase the speed of weight transfer, letting you more quickly and predictably redistribute the weight of the car with acceleration and braking. However, too-stiff shocks can overpower the springs, reducing their effectiveness at dealing with imperfections in the road and contributing to a loss of traction on uneven road surfaces, including bumps, dips and rumble strips.
Dampers (Extension): Softer<===>Harder
Dampers (Compression): Softer<===>Harder
Anti-Roll Bars
Anti-roll bars increase the vehicle's rigidity and stability under hard cornering by effectively tying together the left and right sides of the vehicle. Hard corners will cause the body of a car to roll away from the turn. You can adjust the stiffness of anti-roll bars to counter the body roll and tweak the cornering characteristics of your vehicle.
Generally, increasing front anti-roll bar stiffness will also increase the tendency to understeer. Conversely, increasing the stiffness of the rear anti-roll bars will increase the tendency to oversteer. It's a good idea to tweak the stiffness to an even level that suits the vehicle before adjusting for understeer or oversteer. When it comes time for the fine-tuning, it's often better to soften the anti-roll bars to correct understeer and oversteer rather than stiffen. If the anti-roll bars are too stiff, you'll get some instability on rough roads and hairiness in tight corners where the inside tires may lift off the ground.
Anti-Roll Bars: Looser<===>Stiffer
Camber Angle
Camber deals with the tilt of the wheels when viewed from the face of the car. Wheels with the tops tilted inward have negative camber, while wheels with the tops tilted outward have positive camber. There's generally no racing application for positive camber, though some degree of negative camber can help cornering. As the car hits hard into a corner, centrifugal force will naturally roll the weight of the vehicle outwards. Negative camber helps keep the tire flat on the asphalt during this weight transfer. However, too much negative camber will prevent the tires from sitting flat during straight acceleration and braking, reducing grip in those situations.
Camber Angle (-): Positive<===>Negative
Note: You cannot have a positive Camber Angle in GT5. Remember 0 is neutral and is neither positive nor negative.
Toe Angle
Toe is the tilted angle of the wheels when viewed from above the car. Positive toe moves the fronts of the wheels inward together, while negative toe has the fronts of the wheels pointed outward, away from each other. The effects of toe are limited, other than affecting tire wear, though a little positive toe can give the characteristic of understeer, while a little negative toe can give the characteristic of oversteer.
Toe Angle: Negative<===>Positive
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Source:
IGN
