Friction and Tires
Whether you're driving a small go-cart, a race-car, or a big 18 wheeler, you must have friction to move forward. Actually, you can't even walk without friction. So, let's dive into what that means.
By definition, friction is the resisting force between two objects as they move over one another. Simply put, friction is the force that holds back the movement of a sliding object.
On a microscopic level, surfaces are not as smooth as they appear to the naked eye. There are a great deal of peaks, valleys, and roughness to even a super smooth pool ball on a felt table.
As two surfaces meet, these peaks and valleys grab onto each other and that is what restricts them from moving and sliding. (example: the bottom of your shoes touching the ground)
When a car tire touches the road, the friction between the rubber on the tire and the road grip together and allow the car to move forward, slow down, and prevent movement until you start driving.
In motorsports, friction is everything. Traction is the more commonly used term and it is most commonly used to describe the amount friction, adhesion, or "grip" the tires have on the race-track.
When driving on track, race-car drivers are highly trained to drive their tires to the limit and maximize all of the friction and grip they have so they be as fast as possible.
Unfortunately, when that limit is reached, and exceeded, the tires will lose grip and the car will start to "slip" and the driver will no longer have control of the car.
At that point, there are certain maneuvers drivers are trained to perform in order to "save the car" -- and regain traction/friction -- but it is not always guaranteed and depends on the circumstance. Therefore, in some cases, the driver will unfortunately crash.
The tires are the only part of a car that actually touch the road, so it is widely agreed that the tires are the most important part of both regular cars and race-cars.