-> Traction Multiplier and Traction Loss
This will be the road/tires friction value. If it's too high, the tires just won't drift, like they were glued to the ground, and if it's too low, the tires will drift like you were wearing fluffy socks on a waxed floor
The difference between these two, is that the Multiplier one will only affect the cornering grip, if it's too high you'll probably be cornering like "Herbie" (or crash if you don't have a proper suspension). The Loss one is the grip when accelerating or braking, if it's too low your car will be on a burnout for a quite long time .
-> Traction Bias
This one, many people doesn't give much importance, but IT IS IMPORTANT!. When driving a car, we must know what drivetrain it has: 4WD, RWD or FWD. And the tires must be addapted to any of those situations, or else, it'll be a difficult ride.
Have you ever noticed why, let's say, a Corvette has the rear tires larger than the front ones? It's a RWD, if so, it needs more grip power in the back than in the front.
GTA SA, isn't THAT realistic, but follows the the same thought: 0.5 is the default value, it means the tires are all the same (good for 4WD or FWD), but if you lower the number, let's say, to 0.47, you'll be shifting the grip backwards (good for RWD), and if you raise the number, you'll be shifting the grip forward (good for FWD drifting).
I hope I answered your question
Edited by Edward_FFS, 21 January 2012 - 11:56 AM.