It is possible for tires to lose grip when they're spinning too fast or too slow in relation to the ground under them, or when they're going sideways and trying to give it a big PUSH. Basically, all the circumstances that would cause the sound of tires screeching in real life are something that you can actually have the vehicle react to.
StaticFriction is how much friction the tire has under normal circumstances. Driving slowly, turning gradually, and keeping solid contact with the ground will generally keep your tires under the influence of staticFriction. The higher staticFriction is, and the higher values like lateralForce and longitudinalForce are, the less likely you are to lose it.
When the tires lose contact with the ground, they'll usually start spinning at a different speed. When they meet the ground again, they're not synchronized, and the tires lose grip. They are then using kineticFriction until they stop sliding, and their spin rate meets up with the ground again.
Tires will also lose staticFriction and drop to kineticFriction if the engine is very powerful, and causes the powered wheels to spin. This is especially noticeable on cars which don't have all four wheels powered.
If static is the same as kinetic, you will never feel this difference.
If kinetic is higher than static, when you lose grip, you'll gain more grip. Effectively, both have the higher value.
KineticFriction is certainly not limited to left and right directions, as a kineticFriction of 0 can make it impossible to move forward.
An example of staticFriction and kineticFriction in action is my F1 '67.
F167RearTire has the following values:
staticFriction = 3.5;
kineticFriction = 2.9;
The front wheels have 4 and 4. Also, only the rear wheels are powered.
This means that going over bumps while going around a turn or staying on the throttle while turning too sharply can result in a loss of control. Letting go of the throttle and countersteering can allow the rear tires to regain their normal grip.
https://www.youtube.com/watch?v=F4J3dTavlEE&t=1m26sOn the first turn, I'm fine, as my movements are gradual and my wheels stay in contact with the road.
I'm also fine on this sudden evasive move, as I'm at high speed. This one doesn't make as much realistic sense.
The slower you're going, the greater the difference is between your current speed and your maximum speed.
The closer you are to maximum speed, the less the powered wheels can do about it.
In other words, the slower you're going, the more difference there is to make up, and the harder the engine pushes.
So, in a rear wheel drive vehicle with slippery tires, the slower you are, the more the tires will slip if you use the throttle.
At high speed, the throttle won't make a ton of difference in how fast the tires are spinning, and you can stay in control in a short swerve.
However, at high speed, if you try to go into a long or sharp turn, you're asking a lot more of the tires than if you took that turn at low speed, and the lateral force can fail you, causing a loss of grip.
Here, I go over a bump. The rear wheels lose contact. However, I'm using the brake, which keeps the car under control.
At this point, I lose contact again, and I'm using the throttle, but I'm not turning at all. Traveling in a straight line, the wheels are able to synchronize with the ground before the loss of grip makes a difference.
Finally, at this point, my tires lose contact for a moment, I'm using the throttle, AND I'm turning, all at once.
When the right rear wheel got onto the grass, most of the weight was on it, giving it more to do, and causing it to slip.
When the right wheel comes down off the grass, it loses contact with the road, ensuring it still has no grip. The left rear tire cannot compensate.
With both rear tires having reduced grip (based on the kineticFriction value) the car oversteers. In other words, the rear of the car swings around, turning me more than expected.
I attempt to countersteer, but I've already lost it.